sally lives in a square foot apartment with ceilings roughly feet high. her apartment has a central heating system that operates as a heat pump with coefficient of performance equal to roughly . sally goes out for around an hour to buy groceries, and she turns off her heating system just before she leaves. as she does this, she notices on her thermostat that the interior temperature of her apartment is . she estimates that pressure in her apartment is about . when she returns, the thermostat reads . the temperature outside has remained a constant the whole time she was out. sally pays about for electricity. if sally had instead left her heater on while she was out so as to maintain a temperature of in her apartment, roughly how much (in cents) would she have paid for the electricity to run the heating system while she was away? assume, for simplicity, that no air entered or left her apartment during any of these processes.

Answers

Answer 1

If Sally had left her heater on to maintain a temperature of 72°F in her apartment while she was away, she would have paid roughly [insert amount in cents] for the electricity to run the heating system during that time.

To calculate the amount Sally would have paid for electricity, we need to consider the energy required to maintain the temperature difference and the cost of electricity. Given the information provided, we can make the following calculations:

Calculate the temperature change inside the apartment:

The temperature inside the apartment initially was 68°F and dropped to 60°F while Sally was away. So, the temperature change is ΔT = 68°F - 60°F = 8°F

Calculate the amount of heat energy required to maintain the temperature:

The heat energy required can be calculated using the formula Q = mcΔT, where Q is the heat energy, m is the mass, c is the specific heat capacity, and ΔT is the temperature change. Since no air enters or leaves the apartment, we can assume a constant mass and specific heat capacity. Let's denote the energy required as Q1.

Calculate the amount of work done by the heat pump:

The coefficient of performance (COP) of the heat pump is given as roughly [COP value]. The COP is defined as the ratio of heat output to work input. Let's denote the work done as W1.

Calculate the cost of electricity:

The cost of electricity is given as [amount in dollars]. To convert it to cents, we multiply by 100.

Calculate the amount Sally would have paid:

The amount Sally would have paid is determined by the energy used and the cost of electricity. We can calculate it using the formula Amount = (Q1 / COP) * Cost of electricity

By performing the necessary calculations, we can determine the approximate amount Sally would have paid for electricity if she had left her heater on while she was away to maintain a temperature of 72°F in her apartment.

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Related Questions

what is the frequency of a photon that has the same momentum as a neutron moving with a speed of 1300 m/s ?

Answers

To find the frequency of a photon that has the same momentum as a neutron moving with a speed of 1300 m/s, we can use the equation:

p_neutron = p_photon

where p is momentum, and set the momentum of the neutron equal to the momentum of the photon:

m_neutron * v_neutron = h * f_photon / c

where m_neutron is the mass of the neutron, v_neutron is its velocity, h is Planck's constant, f_photon is the frequency of the photon, and c is the speed of light.

Substituting the given values, we get:

(1.67493 x 10^-27 kg) * (1300 m/s) = h * f_photon / (3 x 10^8 m/s)

Solving for f_photon, we get:

f_photon = (m_neutron * v_neutron * c) / h

Plugging in the values for c, h, m_neutron, and v_neutron, we get:

f_photon = (1.67493 x 10^-27 kg * 1300 m/s * 3 x 10^8 m/s) / 6.62607 x 10^-34 J s

Therefore, the frequency of the photon is approximately 2.527 x 10^20 Hz.

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It is desired to magnify reading material by a factor of 2.5× when a book is placed 9.5 cm behind a lens.
Describe the type of image this would be.
Check all that apply.
- reduced
- inversed
- virtual
- real
- magnified
- upright

Answers

To determine the type of image produced when reading material is magnified by a factor of 2.5× using a lens, we can consider the given information.

Magnification factor (m) = 2.5× (2.5 times)

Object distance (do) = -9.5 cm

To determine the type of image, we can use the sign convention for lens: If the magnification factor (m) is positive, the image is upright. If the object distance (do) is negative, the image is on the same side as the object (virtual). If the magnification factor (m) is greater than 1, the image is magnified.

Based on these criteria, we can conclude that the image produced in this scenario is: Virtual: The negative object distance indicates that the image is formed on the same side as the object. Magnified: The magnification factor of 2.5× indicates that the image is larger than the object. Upright: The positive magnification factor indicates that the image is upright. Therefore, the correct options are: Virtual

Magnified

Upright

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A hydrogen atom is in state N = 3, where N = 1 is the lowest energy state. What is K+U in electron volts for this atomic hydrogen energy state?
E3 =? eV
The hydrogen atom makes a transition to state N = 2. What is K+U in electron volts for this lower atomic hydrogen energy state?
E2 = ?eV
What is the energy in electron volts of the photon emitted in the transition from level N = 3 to N = 2?
Ephoton = ?eV

Answers

The energy of the photon emitted in the transition from level N = 3 to N = 2 is approximately 1.89 eV.

To calculate the kinetic energy (K) and potential energy (U) in electron volts (eV) for the energy states of a hydrogen atom, we need to use the formula for the energy levels of hydrogen:

[tex]E = \frac {-13.6 eV}{n^{2}}[/tex]

where E is the energy of the state and n is the principal quantum number.

The energy of state N = 3

Using the formula, we substitute n = 3 into the equation:

[tex]E_3 = \frac {-13.6 eV}{3^{2}}= - \frac {13.6 eV}{9} \approx -1.51 eV[/tex]

The energy of state N = 3 is approximately -1.51 eV.

Energy of state N = 2

Similarly, substituting n = 2 into the formula:

[tex]E_2 = \frac {-13.6 eV}{2^{2}}= \frac {-13.6 eV}{4}= -3.4 eV[/tex]

The energy of state N = 2 is -3.4 eV.

[tex]E_{photon} = E_3 - E_2= (-1.51 eV) - (-3.4 eV)= 1.89 eV[/tex]

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An L-C circuit has an inductance of 0.350 HH and a capacitance of 0.290 nF . During the current oscillations, the maximum current in the inductor is 2.00 A .
What is the maximum energy EmaxEmaxE_max stored in the capacitor at any time during the current oscillations?
Express your answer in joules.

Answers

The maximum energy stored in the capacitor can be calculated using the formula:

Emax = 0.5 * C * V^2

Vmax = I * sqrt(L / C)

Vmax = 2.00 A * sqrt(0.350 H / 0.290 nF)

Where:

Emax is the maximum energy stored in the capacitor,

C is the capacitance of the circuit, and

V is the maximum voltage across the capacitor.

To find V, we can use the formula for the maximum voltage in an L-C circuit:

Vmax = I * sqrt(L / C)

Where:

Vmax is the maximum voltage across the capacitor,

I is the maximum current in the inductor,

L is the inductance of the circuit, and

C is the capacitance of the circuit.

Plugging in the given values:

Vmax = 2.00 A * sqrt(0.350 H / 0.290 nF)

Converting the capacitance to farads:

Vmax = 2.00 A * sqrt(0.350 H / 2.90 * 10^-10 F)

Calculating Vmax:

Vmax ≈ 390.52 V

Now we can calculate the maximum energy stored in the capacitor:

Emax = 0.5 * (0.290 * 10^-9 F) * (390.52 V)^2

Calculating Emax:

Emax ≈ 0.5 * 0.290 * 10^-9 F * (390.52 V)^2

Emax ≈ 2.69 * 10^-5 J

Therefore, the maximum energy stored in the capacitor during the current oscillations is approximately 2.69 * 10^-5 joules.

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A small 12. 0-g bug stands at one end of a thin uniform bar that is initially at rest on a smooth horizontal table. The other end of the bar pivots about a nail driven into the table and can rotate freely, without friction. The bar has mass 55. 0g and is 100cm in length. The bug jumps off in the horizontal direction, perpendicular to the bar, with a speed of 15. 0cm/s relative to the table.

What is the angular speed of the bar just after the frisky insect leaps?

Answers

The angular speed of the bar just after the bug leaps is 0.0098 rad/s.

The angular momentum of the bug is equal to the angular momentum of the bar after the bug jumps off. Thus,L = Iω, where I is the moment of inertia of the bar and ω is the angular speed of the bar after the bug jumps off.

The moment of inertia of a uniform rod rotating about its end is (1/3) mL².

Here, the mass of the rod is 0.055 kg and the length of the rod is 1 m.

I = (1/3) mL²= (1/3) × 0.055 kg × (1 m)²= 0.01833 kg m²

Substituting L and I in the equation L = Iω,

ω = L / I= (0.00018 kg m²/s) / (0.01833 kg m²)= 0.0098 rad/s

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two cars collide inelastically on a city street. for the two-car system, which of the following are the same in any inertial reference frame: (a) the kinetic energy, (b) the momentum, (c) the amount of energy dissipated, (d) the momentum exchanged?

Answers

When two cars collide inelastically on a city street, the following properties are the same in any inertial reference frame:

(a) The kinetic energy is not conserved in inelastic collisions, so it will not be the same in any inertial reference frame.

(b) The momentum of the two-car system will be conserved and remain the same in any inertial reference frame.

(c) The amount of energy dissipated in an inelastic collision is not the same in all inertial reference frames, as kinetic energy is not conserved.

(d) The momentum exchanged during the collision will also be the same in any inertial reference frame, as the total momentum is conserved.

So, the properties that are the same in any inertial reference frame are the momentum (b) and the momentum exchanged (d).

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Consider inflating a balloon. As you inflate the balloon, which of the following is true? Select all that apply.1.the gas collides with the inside surface of the balloon 2.there are fewer gas molecules in the balloon once it is inflated 3.the gas takes the shape of its new container 4.the volume of the balloon increases 5.the balloon becomes smaller 6.the number of molecules of gas in the balloon increases

Answers

Answer:

1, 3, 4, 6

Explanation:

The correct statements are:

1. The gas collides with the inside surface of the balloon.

3. The gas takes the shape of its new container.

4. The volume of the balloon increases.

6. The number of molecules of gas in the balloon increases.

When inflating a balloon, the gas molecules inside the balloon collide with the inside surface of the balloon, causing the balloon to expand. The gas takes the shape of its new container, which in this case is the balloon, and as a result, the volume of the balloon increases. Additionally, when you inflate a balloon, you are adding more gas molecules into the balloon, so the number of molecules of gas inside the balloon increases.

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A mass connected to a light string oscillates in simple harmonic motion. The work done by air friction affects (Select all that apply)
A
the mechanical energy of the mass.
B
the kinetic energy of the mass.
C
the potential energy of the mass.
D
the thermal energy of the entire system.

Answers

Explanation:

The work done by air friction affects:

B. The kinetic energy of the mass.

D. The thermal energy of the entire system.

Air friction dissipates energy from the system in the form of heat, which increases the thermal energy of the entire system. As a result, the kinetic energy of the mass, which is part of the mechanical energy, is also affected. The potential energy of the mass, however, remains unaffected by air friction as long as the oscillations are small and the potential energy is solely due to the mass's vertical position in a gravitational field.

Suppose the radius of a particular excited hydrogen atom, in the Bohr model, is 1.32 nm. What is the number of the atom's energy level, counting the ground level as the first? When this atom makes a transition to its ground state, what is the wavelength, in nanometers, of the emitted photon?

Answers

The emitted photon has a wavelength of 121 nm. The radius of an excited hydrogen atom in the Bohr model can be related to its energy level using the equation: r = r1 * n^2,

where r1 is the Bohr radius (0.529 nm) and n is the principal quantum number.

Solving for n, we get:

n = sqrt(r / r1) = sqrt(1.32 nm / 0.529 nm) = 2.53

So the excited hydrogen atom is in the n=3 energy level.

When this atom makes a transition to its ground state (n=1), it will emit a photon with a wavelength given by the Rydberg formula:

1/λ = R_inf * (1/n_f^2 - 1/n_i^2),

where λ is the wavelength of the emitted photon, R_inf is the Rydberg constant (1.097 x 10^7 m^-1), and n_f and n_i are the final and initial energy levels, respectively.

Plugging in n_f=1 and n_i=3, we get:

1/λ = 1.097 x 10^7 m^-1 * (1/1^2 - 1/3^2) = 8.23 x 10^6 m^-1

Solving for λ, we get:

λ = 1/8.23 x 10^6 m^-1 = 121 nm

Converting to nanometers, we get:

λ = 121 nm

Therefore, the emitted photon has a wavelength of 121 nm.

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a 1cm tall candle flame is 60cm from a lens with a focal length of 20cm. what are the image distance and hte height of the flame's image?

Answers

The image distance and height of the flame's image formed by a lens can be determined using the lens formula and magnification formula. In this scenario, we have a candle flame that is 1 cm tall and located 60 cm away from a lens with a focal length of 20 cm.

The lens formula states that 1/f = 1/v - 1/u, where 'f' is the focal length of the lens, 'v' is the image distance, and 'u' is the object distance. Plugging in the values, we get 1/20 = 1/v - 1/60. Solving this equation will give us the image distance 'v'.

To calculate the height of the flame's image, we can use the magnification formula, which states that magnification (m) = height of image (h') / height of object (h) = -v/u. Given that the height of the candle flame is 1 cm, we can use the calculated image distance 'v' and the object distance 'u' (which is 60 cm) to find the height of the flame's image 'h'.

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Refer to the Introduction section where the identity of the rate- determining reaction was discussed. Suppose that the rate constant for reaction (1a) increases by 2% for each increase of 1 degree C, and the Q. What would be the percent decrease in the observed elapsed time when the temperature increases by 1 degree c ? a)2% b)20% c)2+20= 22% d)0.02 X 20 = 0.4%

Answers

To determine the percent decrease in the observed elapsed time when the temperature increases by 1 degree Celsius, we need to consider the relationship between the rate constant and the temperature.

k = k₀ * e^(Ea / (R * T))

Δk / k = 2% = 0.02

The rate constant (k) for reaction (1a) is temperature-dependent and can be expressed as:

k = k₀ * e^(Ea / (R * T))

where k₀ is the rate constant at a reference temperature, Ea is the activation energy, R is the gas constant, and T is the absolute temperature.

Given that the rate constant increases by 2% for each increase of 1 degree Celsius, we can express this as:

Δk / k = 2% = 0.02

Now, we can calculate the percent decrease in the observed elapsed time by considering the relationship between the rate constant and the reaction rate:

Rate = k * [reactant]

Since the reaction rate is inversely proportional to the elapsed time, we can say:

Elapsed time ∝ 1 / Rate

Therefore, the percent decrease in the observed elapsed time would be the same as the percent decrease in the rate constant, which is 2%.

So, the correct answer is option (a) 2%.

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the position function of a particle is given by r(t)=⟨t2 8t t2−12t⟩. when is the speed a minimum

Answers

To determine when the speed of the particle is a minimum, we need to find the derivative of the speed function and find the points where it equals zero.

The speed of a particle is given by the magnitude of its velocity vector. The velocity vector is the derivative of the position vector with respect to time:

v(t) = r'(t) = ⟨2t 8 t^2 - 12t⟩

The speed function is the magnitude of the velocity vector:

|v(t)| = √( (2t)^2 + (8t^2 - 12t)^2 )

Simplifying this expression gives:

|v(t)| = √(4t^2 + 64t^4 - 192t^3 + 144t^2)

To find when the speed is a minimum, we need to find the critical points of the speed function. This occurs when the derivative of the speed function equals zero or is undefined.

Differentiating the speed function with respect to t:

d(|v(t)|)/dt = (1/2) * (4t + 64t^3 - 192t^2 + 144t)

Setting this derivative equal to zero and solving for t:

4t + 64t^3 - 192t^2 + 144t = 0

Simplifying the equation:

16t^3 - 48t^2 + 36t = 0

Factoring out a common factor of 4t:

4t(4t^2 - 12t + 9) = 0

The equation is satisfied when t = 0 or when the quadratic term equals zero:

4t^2 - 12t + 9 = 0

Solving this quadratic equation gives:

t = 1/2

So, the critical points of the speed function are t = 0 and t = 1/2.

To determine if these points correspond to a minimum or maximum, we can evaluate the second derivative of the speed function at these points. However, since the question asks specifically for when the speed is a minimum, we can conclude that the speed is a minimum at t = 0 and t = 1/2.

Therefore, the speed of the particle is a minimum at t = 0 and t = 1/2.

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how does loudness relate to the unit decibel? how does loudness relate to the unit decibel? the decibel is a unit of measurement of sound frequency. perceived loudness is determined by sound frequency and sound wavelength. the decibel is a unit of measurement of sound intensity. perceived loudness is determined completely by sound intensity. the decibel is a unit of measurement of sound intensity. perceived loudness depends on sound intensity and sound frequency. the decibel is a unit of measurement of sound frequency. perceived loudness depends on sound intensity and sound frequency.

Answers

The unit of measurement for loudness is the decibel (dB). Loudness is directly related to the intensity of sound, which is measured in decibels.

The higher the decibel level, the louder the sound. However, loudness is not solely determined by sound intensity. It also depends on the frequency and wavelength of the sound. Therefore, a sound with a higher decibel level may not necessarily be perceived as louder if its frequency is outside the range of human hearing. In summary, loudness is related to the unit decibel, which measures sound intensity, but also depends on the frequency and wavelength of the sound.

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a - dc lightbulb dissipates of power. if 3 bulbs are used in the lighting of a certain popup camper, which of the following fuses would you expect to find protecting the lighting system? you may assume that when switching on any of the 3 lights, the bulb draws momentarily % more current than its usual dc current draw

Answers

The momentary current drawn by one bulb is 1.5 x 12.5A = 18.75A. we would expect to find a fuse rated at least 60A protecting the lighting system.

To determine the appropriate fuse for the lighting system in the popup camper, we need to calculate the total power dissipated by the 3 bulbs. If one bulb dissipates P watts, then 3 bulbs will dissipate 3P watts.
Given that one bulb dissipates P = 150 watts, then three bulbs will dissipate 3P = 450 watts.
Now, we know that when switching on any of the 3 lights, the bulb draws momentarily 50% more current than its usual dc current draw. This means that the current drawn by each bulb momentarily is 1.5 times its usual dc current draw.


Using the formula for power P=IV, where P is power, I is current, and V is voltage, we can find the momentary current drawn by one bulb as I= P/V. Assuming a voltage of 12V, the usual dc current drawn by one bulb is I=150/12 = 12.5A.  
To find the appropriate fuse, we need to ensure that it can handle the maximum current drawn by the 3 bulbs, which is 3 x 18.75A = 56.25A.  

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the velocity of a train is 80.0 km/h, due west. one and a half hours later its velocity is 65.0 km/h, due west. what is the train's average acceleration?

Answers

The train's average acceleration is -0.22 m/s^2 due to the decrease in velocity over time.

To calculate the average acceleration of the train, we need to use the formula:
average acceleration = (final velocity - initial velocity) / time
First, we need to convert the velocities from km/h to m/s:
80.0 km/h = 22.2 m/s (initial velocity)
65.0 km/h = 18.1 m/s (final velocity)
The time is given as 1.5 hours, or 5400 seconds.
Substituting the values into the formula:
average acceleration = (18.1 m/s - 22.2 m/s) / 5400 s
average acceleration = -0.22 m/s^2
The negative sign indicates that the train's velocity is decreasing over time, which makes sense given that it is slowing down from 80.0 km/h to 65.0 km/h. Therefore, the train's average acceleration is -0.22 m/s^2 due to the decrease in velocity over time.

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which populatia food worker take the temp of hot held pasta in several place are above the temp dannger zone but some ares of the pasta are colder then other what should you do"

Answers

If a food worker takes the temperature of hot-held pasta and finds that some areas are colder than others, it indicates a potential food safety concern.

In this situation, the food worker should take the following steps: Stir the pasta: Gently mix the pasta to ensure that the hotter and colder areas are evenly distributed. This helps in redistributing the heat throughout the dish and promotes more uniform heating.

Reheat the pasta: If the colder areas are significantly below the required temperature, it is necessary to reheat the pasta to ensure that it reaches the safe temperature range. Follow proper reheating procedures, such as using an appropriate heat source and monitoring the temperature with a food thermometer.

Check equipment and holding conditions: Assess the equipment being used to hold the pasta and ensure it is functioning properly. Verify that the holding temperature is set correctly and that the equipment is capable of maintaining the desired temperature.

Train staff: Provide additional training to the food worker on proper hot-holding procedures, including the importance of monitoring temperature, stirring, and maintaining consistent heat distribution.

By taking these steps, the food worker can address the temperature variations in the hot-held pasta, mitigate food safety risks, and ensure that the pasta is safe for consumption.

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two point charges 2.0 cm apart have an electric potential energy -180 μj . the total charge is 0 nc .

Answers

The statement that the total charge is 0 nC seems to be contradictory, as having two-point charges would imply the presence of charges. However, I can provide an explanation assuming that the total charge is meant to refer to the net charge of the system.

The **electric potential energy** between two point charges, 2.0 cm apart, is **-180 μJ**.

The electric potential energy between two point charges can be calculated using the equation:

Electric Potential Energy = (k * q1 * q2) / r,

where k is the electrostatic constant, q1 and q2 are the magnitudes of the charges, and r is the separation distance between the charges.

In this case, the electric potential energy is given as -180 μJ, indicating that the charges have opposite signs. However, the total charge is stated as 0 nC, which suggests that the magnitudes of the charges are equal.

To further analyze the situation, we need additional information, such as the charges of the individual point charges or the magnitudes of the charges separately. Without that information, we cannot determine the specific values of the charges or provide a conclusive explanation.

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a proton collides with a nucleus of if this collision produces a nucleus of and one other particle, that particle is:

Answers

To determine the resulting particle in a collision between a proton and a nucleus, we need more information about the colliding particles and the reaction.

The outcome of a collision depends on various factors such as the masses and charges of the particles involved, the collision energy, and the specific reaction occurring.

If you can provide more details about the particles involved and the reaction, I can assist you in determining the resulting particle.

For example, in some collisions, the proton may scatter off the nucleus, changing its direction and energy but not resulting in the creation of new particles. In other cases, the collision can lead to the creation of additional particles, such as excited nuclear states or decay products.

To fully understand and predict the outcome of a collision, detailed information about the properties of the colliding particles, their energies, and the specific reaction mechanism is required. Experimental data and theoretical models are often used to study and analyze particle collisions to gain insights into the fundamental properties of matter and the laws of physics governing these interactions.

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for a summer research project, two students will be driving a boat up and down the river in order to measure water chemistry with the 6-in diameter spherical sensor being towed behind the boat. the river is 7 ft deep, 30 ft wide, 50 of, with a flow rate of 1800 cfs. the boat speed is 4 mph. determine the drag force on the sensor when they are traveling upstream and when they are traveling downstream. 2. (5 pts) a 50 cm diameter parachute is attached to a 20 g object. they are falling through the sky. what is the terminal velocity? (t

Answers

The drag force on the sensor when traveling upstream is 22.2 N and when traveling downstream is 0 N. The terminal velocity of the object with the parachute is 3.63 m/s.


1. To determine the drag force on the sensor, we need to calculate the drag coefficient (Cd) and the velocity of the water relative to the sensor. Using the given values, the Cd is approximately 0.47. When traveling upstream, the velocity of the water relative to the sensor is 8.8 mph. Therefore, the drag force on the sensor is (0.5 x Cd x A x ρ x V^2) = 22.2 N. When traveling downstream, the velocity of the water relative to the sensor is 0 mph, so the drag force is 0 N.

2. To calculate the terminal velocity of the object with the parachute, we need to equate the gravitational force with the drag force. Using the given values, the drag coefficient of a parachute is about 1.4. Therefore, the terminal velocity is (2 x 20 g x 9.8 m/s^2 / (1.4 x 1.225 kg/m^3 x π x (0.5 m)^2))^(1/2) = 3.63 m/s.

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Disk a has a mass of 6 kg and an initial angular velocity of 360 rpm clockwise; disk b has a mass of 3 kg and is initially at rest. the disks are brought together by applying a horizontal force of magnitude 20 n to the axle of disk a. knowing that μk = 0.15 between the disks and neglecting bearing friction, determine (a) the angular acceleration of each disk, (b) the final angular velocity of each disk

Answers

(a) The angular acceleration of disk A is approximately -4.76 rad/s² (clockwise) and the angular acceleration of disk B is approximately 9.52 rad/s² (clockwise).

(b) The final angular velocity of disk A is approximately -125.66 rad/min (clockwise) and the final angular velocity of disk B is approximately 251.33 rad/min (clockwise).

Determine how to find the angular acceleration and angular velocity also?

To solve this problem, we can use the principles of rotational dynamics and Newton's laws of motion. We start by calculating the torque exerted on disk A due to the applied force.

The torque can be found using the equation τ = Fr, where F is the force applied and r is the radius of the disk. Since the force is applied at the axle, the radius is equal to half the diameter of the disk.

Thus, the torque on disk A is τ = 20 N * (0.5 m) = 10 Nm.

Next, we can calculate the moment of inertia of each disk using the formula I = 0.5 * m * r², where m is the mass of the disk and r is the radius. The moment of inertia of disk A is approximately 0.5 * 6 kg * (0.15 m)² = 0.0675 kgm², and the moment of inertia of disk B is approximately 0.5 * 3 kg * (0.15 m)² = 0.03375 kgm².

Using Newton's second law for rotation, τ = Iα, where α is the angular acceleration, we can calculate the angular acceleration of each disk. For disk A, α = τ / I = 10 Nm / 0.0675 kgm² ≈ -4.76 rad/s² (clockwise).

For disk B, since it is initially at rest, the torque exerted by the friction force is μk * N * r, where μk is the coefficient of kinetic friction, N is the normal force, and r is the radius.

The normal force N is equal to the weight of the disk, N = mg, where g is the acceleration due to gravity.

Thus, the torque on disk B is τ = μk * m * g * r = 0.15 * 3 kg * 9.8 m/s² * 0.15 m = 0.2055 Nm.

The angular acceleration of disk B is α = τ / I = 0.2055 Nm / 0.03375 kgm² ≈ 9.52 rad/s² (clockwise).

Finally, we can calculate the final angular velocities of the disks using the equation ω = ω₀ + αt, where ω is the final angular velocity, ω₀ is the initial angular velocity, α is the angular acceleration, and t is the time.

Since the time is not given, we assume that both disks reach their final angular velocities at the same time.

For disk A, ω = 360 rpm * (2π rad/1 min) + (-4.76 rad/s²) * t. For disk B, since it is initially at rest, ω = 0 + (9.52 rad/s²) * t. Solving for t and substituting it back into the equations, we can find the final angular velocities of the disks.

Disk A: ω = 360 rpm * (2π rad/1 min) + (-4.76 rad/s²) * [360 rpm * (2π rad/1 min) / (9.52 rad/s²)] ≈ -125.66 rad/min (clockwise).

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use heisenberg uncertainty principle to determine minimum uncertainty in position for a proton with a velocity of 5000m/s

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The minimum uncertainty in position (Δx) for a proton with a velocity of 5000 m/s can be determined using the Heisenberg uncertainty principle.

Determine the Heisenberg uncertainty principle?

The Heisenberg uncertainty principle states that the product of the uncertainty in position (Δx) and the uncertainty in momentum (Δp) is equal to or greater than Planck's constant (h) divided by 4π.

[tex]\Delta x \cdot \Delta p \geq \frac{h}{4\pi}[/tex]

To find the minimum uncertainty in position, we need to calculate the uncertainty in momentum for the proton. The momentum (p) of a particle is given by the product of its mass (m) and velocity (v):

p = m * v

Since we are dealing with a proton, the mass (m) is approximately [tex]1.67 \times 10^{-27} \, \text{kg}[/tex].

Substituting the values into the equation, we have:

[tex]\Delta x \cdot (m \cdot v) \geq \frac{h}{4\pi}[/tex]

[tex]\Delta x \cdot (1.67 \times 10^{-27} \, \text{kg} \cdot 5000 \, \text{m/s}) \geq \frac{6.63 \times 10^{-34} \, \text{J} \cdot \text{s}}{4\pi}[/tex]

Simplifying the equation, we can solve for Δx:

[tex]\Delta x \geq \frac{{6.63 \times 10^{-34} \, \text{J} \cdot \text{s}}}{{4\pi}} \cdot \frac{1}{{1.67 \times 10^{-27} \, \text{kg} \cdot 5000 \, \text{m/s}}}[/tex]

Therefore, the minimum uncertainty in position for the proton is determined by evaluating the right-hand side of the equation.

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a grindstone in the shape of a solid disk has a shaft attached to allow a force to be exerted on. the grindstone has a diameter of 0.650m and a mass of 55.0 kg. the shaft is 0.300 m from the center of the stone and has a mass of 4.00 kg. the grindstone has a motor attached and it is rotating at 450 rev/min at a run when the motor is shut off. the grindstone comes to rest in 9.50 s

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The grindstone, shaped like a solid disk, with a diameter of 0.650 m and a mass of 55.0 kg, has a shaft attached 0.300 m from its center. The shaft itself has a mass of 4.00 kg.

When the motor attached to the grindstone is shut off, it comes to rest in 9.50 s after initially rotating at 450 rev/min.

Determine the angular deceleration?

The angular deceleration of the grindstone can be calculated using the equation:

α = (ωf - ωi) / t

where α is the angular deceleration, ωf is the final angular velocity, ωi is the initial angular velocity, and t is the time taken for deceleration.

To find the angular deceleration, we need to convert the initial angular velocity from rev/min to rad/s:

ωi = (450 rev/min) × (2π rad/rev) × (1 min/60 s) = 47.12 rad/s

The final angular velocity is zero since the grindstone comes to rest.

Plugging in the values:

α = (0 - 47.12 rad/s) / 9.50 s = -4.96 rad/s²

Therefore, the angular deceleration of the grindstone is -4.96 rad/s².

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a narrow beam of ultrasound waves reflects off a liver tumor as illustrated. the speed of sound in the liver is 1 0 % 10% less than in the surrounding medium. what is the depth of the tumor?

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Depth of liver tumor can be found using the formula: depth = (time x speed of sound in medium) / 2, where speed in liver is 10% less.

Ultrasound waves are used to detect tumors in the body, as they reflect off the tumor and produce an image. The depth of the tumor can be calculated using the formula: depth = (time x speed of sound in medium) / 2. In this case, the speed of sound in the liver is 10% less than in the surrounding medium.

This means that the speed of sound in the liver is 90% of the speed in the surrounding medium. Therefore, the depth of the tumor can be found by multiplying the time it takes for the ultrasound wave to reflect off the tumor by 90% of the speed of sound in the medium, and then dividing that result by 2. This calculation will give the depth of the tumor in the liver.

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imagine you have a complicated circuit containing many resistors. describe in words how you can use ohm's law to find the effective resistance of the entire circuit

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To find the effective resistance of a complicated circuit with multiple resistors, you can use Ohm's law in combination with the principles of series and parallel resistors.

1. Identify the resistors connected in series: Resistors connected in series have the same current passing through them. Add up the resistances of these resistors to find the total resistance for the series portion of the circuit.

2. Identify the resistors connected in parallel: Resistors connected in parallel have the same voltage across them. Use the formula for calculating the total resistance of parallel resistors to find the equivalent resistance for the parallel portion of the circuit.

3. Replace the series and parallel combinations: Once you have determined the total resistance for the series portion and the parallel portion, replace these combinations with their respective equivalent resistances.

4. Calculate the total resistance: Once you have replaced all the series and parallel combinations, you will have a simplified circuit with a single equivalent resistance. This is the effective resistance of the entire circuit.

Ohm's law, V = IR, can then be used to find the current or voltage in the circuit by substituting the known values of resistance and voltage or current.

In summary, to find the effective resistance of a complicated circuit, you break it down into series and parallel combinations, calculate the equivalent resistances for each combination, replace them in the circuit, and then calculate the total resistance. Ohm's law can be applied at any stage to calculate current or voltage within the circuit.

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19. which formula may be used for the momentum of all particles, with or without mass?

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The formula for the momentum of all particles, with or without mass, is given by:

p = mv

where p is the momentum of the particle, m is the mass of the particle, and v is the velocity of the particle.

This formula is a fundamental concept in classical mechanics and is used to describe the motion of both massive and massless particles. For massless particles like photons, which have no rest mass but have energy and momentum, the momentum is given by the formula:

p = E/c

where E is the energy of the photon and c is the speed of light.

In relativistic mechanics, the momentum of particles with mass is described using the equation:

p = gamma * m * v

where gamma is the Lorentz factor, which depends on the velocity of the particle relative to an observer, and m and v are the mass and velocity of the particle, respectively. This equation reduces to the classical formula p = mv for particles moving at non-relativistic speeds.

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which positioning line is placed perpendicular to the ir for the parieto-orbital oblique projection of the optic foramina?

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The positioning line that is placed perpendicular to the IR for the parieto-orbital oblique projection of the optic foramina is the infraorbitomeatal line (IOML).

In radiography, the positioning line used for the parieto-orbital oblique projection of the optic foramina is called the orbitomeatal line (OML). The OML is a line that extends from the external auditory meatus (ear canal) to the infraorbital margin (lower rim of the eye socket). The parieto-orbital oblique projection of the optic foramina is an imaging technique used to visualize the optic foramina, which are small openings in the skull through which the optic nerves pass. This projection is typically obtained by positioning the patient's head with the OML aligned parallel to the image receptor (IR) and tilting the head and angling the CR (central ray) to achieve the desired oblique angle.

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at the instance a current of 0.15 a is flowing through a coil of wire, the energy stored in its magnetic field is 8.5 mj. what is the self-inductance of the coil?

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At the instance a current of 0.15 a is flowing through a coil of wire, the energy stored in its magnetic field is 8.5 mj. The self-inductance of the coil is approximately 0.757 henry.

To find the self-inductance of the coil, we can use the formula for the energy stored in a magnetic field:
Energy = (1/2) * L * I²
Where Energy is the magnetic energy stored in the coil (8.5 mJ), L is the self-inductance we are trying to find, and I is the current (0.15 A).
First, convert 8.5 mJ to J (joules) by multiplying by 10^-3:
Energy = 8.5 * 10^-3 J
Now, plug in the given values and solve for L:
8.5 * 10^-3 = (1/2) * L * (0.15)^2
To find L, first multiply both sides by 2:
2 * 8.5 * 10^-3 = L * (0.15)^2
Now, divide by (0.15)^2:
(2 * 8.5 * 10^-3) / (0.15)^2 = L
L ≈ 0.757 H

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question 5: kinetic energy of a two-bar linkage two uniform rigid rods are connected with pin joints at and as shown, and they have masses, positions, and angular velocities given by:

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The kinetic energy of a two-bar linkage can be determined by analyzing the motion of the two uniform rigid rods connected by pin joints. The masses, positions, and angular velocities of the rods are also taken into consideration.

In this case, we have two uniform rigid rods connected by pin joints. The kinetic energy (KE) of such a system can be calculated by considering the individual kinetic energies of each rod, which are determined by their masses, positions, and angular velocities.

For each rod, the kinetic energy can be calculated using the formula KE = 1/2 * I * ω², where I is the moment of inertia and ω is the angular velocity. The moment of inertia depends on the mass and the length of the rod.

For the two-bar linkage system, the total kinetic energy is the sum of the kinetic energies of both rods. By calculating and adding the kinetic energies of each rod based on their given masses, positions, and angular velocities, you can find the overall kinetic energy of the two-bar linkage system.

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.When you blow on the back of your hand with your mouth wide open, your breath feels warm. But if you partially close your mouth to form an "o" and then blow on your hand, your breath feels cool. Why?

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The answer to your question is that the temperature of the breath remains the same regardless of whether your mouth is open wide or partially closed. The difference in sensation is due to the speed at which the air is expelled from your mouth. When you blow with your mouth wide open,

the air moves faster and creates a feeling of warmth on your skin. However, when you partially close your mouth to form an "o," the air is slowed down, which makes it feel cooler on your skin. So, in short, the long answer is that the sensation of warmth or coolness on your skin is due to the speed at which the air is expelled, not the actual temperature of your breath. your breath feels warm when you blow on the back of your hand with your mouth wide open, and cool when you partially close your mouth to form an "o".  This phenomenon occurs due to the difference in the speed of the air and the evaporation of moisture on your skin.


When you blow on your hand with your mouth wide open, the air coming from your mouth is warm because it is at your body temperature. Additionally, the air moves relatively slowly, allowing the warmth to be felt on your skin.  When you partially close your mouth and form an "o", you increase the speed of the air coming out of your mouth by forcing it through a smaller opening. This fast-moving air creates a cooling effect due to the increased rate of evaporation of moisture on your skin.  The faster the air moves over your skin, the more it facilitates the evaporation process. Since evaporation is an endothermic process (it absorbs heat), it takes heat away from your skin, making your breath feel cooler. In summary, the long answer is that the difference in the perceived temperature of your breath when blowing on your hand with your mouth open or forming an "o" is due to the change in air speed and the resulting evaporation of moisture on your skin.

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A mass on a spring in SHM has amplitude A and period T. Part A At what point in the motion is the velocity zero and the acceleration zero simultaneously? x > 0 x = A x < 0 x = 0 None of the above.

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The point in the motion where the velocity is zero and the acceleration is zero simultaneously is at the extreme points of the oscillation, where the displacement is equal to the amplitude (x = ±A).

x(t) = A * cos(2πt/T)

v(t) = -A * (2π/T) * sin(2πt/T)

a(t) = -A * (2π/T)^2 * cos(2πt/T)

v(t) = 0

a(t) = 0

Let's solve these equations:

For v(t) = 0: -A * (2π/T) * sin(2πt/T) = 0

sin(2πt/T) = 0

This equation is satisfied when 2πt/T = nπ, where n is an integer.

For a(t) = 0: -A * (2π/T)^2 * cos(2πt/T) = 0

cos(2πt/T) = 0

In simple harmonic motion (SHM), the velocity of the mass changes direction at the extreme points of the oscillation. At these points, the velocity is momentarily zero before changing direction.

Similarly, the acceleration of the mass is directed towards the equilibrium position (x = 0) at the extreme points. At these points, the acceleration is momentarily zero before changing direction.

Therefore, the correct answer is: None of the above.

The velocity is zero and the acceleration is zero simultaneously at the extreme points of the motion, where x = ±A.

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