The sound level from 1 km away is 46.4 dB and the sound energy radiated through the windows and doors in 20 min is 332.6 J
What do you mean by sound radiates?Multiple plate modes participate in the forced vibration of a baffled plate that produces sound. The emitted sound power depends on the activation of each plate mode by the external pressures as well as the radiation characteristics of the individual plate modes and their mutual interaction via their radiated sound, as shown in eq (20) and (24). The net contribution of the mutual interaction between plate modes to the overall sound power may be disregarded if a plate is activated in a manner that results in a plate vibration field that can be defined as reverberant with an equal distribution of energy over all modes.
(Lw) = 10·log (W/Wo) dB
Given:
sound level, [tex]\beta= 101 dB[/tex]
Area, A = [tex]22\;m^{2}[/tex]
Time, [tex]\triangle t = 20\;min=1200\;s[/tex]
Intensity, [tex]I=1\times 10^{-12}\;W/m^{2}[/tex]
[tex]r=1\;km=1000\;m[/tex]
(a)
We know that, Sound level is,
[tex]\beta=10\times log(\frac{I}{I_{o} } )[/tex]
Solving the above equation for sound intensity,
[tex]I=I_{o} \times 10^{\frac{\beta}{10} }[/tex]
[tex]I=1 \times 10^{-12} \times 10^{\frac{101}{10} }[/tex]
[tex]I=0.0126\;W/m^{2}[/tex]
Therefore, The sound energy is,
[tex]E=P\times \triangle t[/tex]
Substitute [tex]P=I \times A[/tex] in the above equation,
[tex]E=I \times A \times \triangle t[/tex]
[tex]E=0.0126 \times 22 \times 1200[/tex]
[tex]E=332.6\;J[/tex]
(b)
Half of a sphere area with 1 km radius is equal to Area of the sound at 1 km distance,
[tex]A_{hemisphere} = \frac{1}{2} \times 4 r^{2} \pi[/tex]
Substitute the known value in the above equation ,
[tex]A_{hemisphere} = \frac{1}{2} \times 4 (1000)^{2} \pi[/tex]
[tex]A_{hemisphere} = 6283185\;m^{2}[/tex]
Sound Intensity is,
[tex]I = \frac{P}{A_{hemisphere}}[/tex]
Substitute [tex]P=I \times A[/tex] in the above equation,
[tex]I = \frac{I \times A}{A_{hemisphere}}[/tex]
Substitute the known value in the above equation,
[tex]I = \frac{0.0126 \times 22}{6283185}[/tex]
[tex]I = 4.4 \times 10^{-8}\;W/m^{2}[/tex]
Sound level is,
[tex]\beta=10\times log(\frac{I}{I_{o} } )[/tex]
Substitute the known value in the above equation,
[tex]\beta=10\times log(\frac{4.4 \times 10^{-8} }{1 \times 10^{-12} } )[/tex]
[tex]\beta=46.4\;dB[/tex]
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Which formula is equivalent to D = m V ?
the earth has a mass of 6x10^24 kg, and a radius of 6400 km. What is the density of the earth in kg/m^2.
The density of the earth is 3.51×10¹⁰ kg/m³
What is Density?Density can be defined as the ratio of mass to the volume of a body. The S.I unit of density is kg/m³
To calculate the density of the earth, we use the formula below.
Formula:
D = m/v............ Equation 1Where:
D = Denstiy of the earthm = Mass of the earthv = Volume of the earthFrom the question,
Given:
m = 6×10²⁴ kgNote: Since the earth is a spherical in shape, we can calculate the volume of the earth using the volume of a sphere
v = 4πr³/3 = (4×3.14×6400000³)/3 = 1.71×10¹⁴ m³Substitute these values into equation 1
D = (6×10²⁴)/(1.71×10¹⁴) D = 3.51×10¹⁰ kg/m³Hence, the density of the earth is 3.51×10¹⁰ kg/m³.
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if a gas occupies 15 l at pressure of 2.3 atm what would the volume be at 3.1 atm
The volume occupied by the gas at 3.1 atm pressure will be 11.12 L.
What is Boyle's Law?When a gas is maintained at a constant temperature and with a certain mass, Boyle's law states that the pressure of the gas is inversely proportional to its volume.
To put it another way, as long as the temperature and volume of the gas remain constant, the pressure and volume of the gas are inversely proportional to one another. In 1662, the Anglo-Irish chemist Robert Boyle proposed the Boyle's law.
According to Boyle's law :
P1V1=P2V2 where,
P1 and P2 are the pressure and,
V1 and V2 are the volume of container.
As per the question, the given values are :
V1=15 L
P1= 2.3 atm and,
P2= 3.1 atm
So by using Boyle's theorem :
2.3 atm× 15 L = 3.1 atm× V2
34.5=3.1 atm × V2
V2=11.12 L
Hence, the volume at 3.1 atm pressure will be 11.12 L.
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Two cats jump off a roof that is 23m off the ground. Cat A jumps directly up with a velocity of 7m/s, and cat B jumps directly down with a velocity of 7m/s. How far up does cat A go? How fast does cat A go just before it hits the ground? How fast does cat B go just before it hits the ground? How much longer is cat A in the air than cat B?
The height reached by cat A is 2.5 m.
The speed of cat A before it hits the ground is 36.4 m/s.
The speed of cat B before it hits the ground is 22.39 m/s.
The time spent in air by cat A than cat B is 1.43 seconds.
Time of motion of cat A
The time of motion of cat A is calculated as follows;
h = vt - ¹/₂gt
-23 = 7t - 4.9t²
4.9t² - 7t - 23 = 0
solve the quadratic equation using formula method;
a = 4.9, b = -7, c = - 23
t = 3.0 seconds
Time of motion of cat BThe time of motion of cat B is calculated as follows;
h = vt - ¹/₂gt
23 = 7t + 4.9t²
4.9t² + 7t - 23 = 0
solve the quadratic equation using formula method;
a = 4.9, b = 7, c = -23
t = 1.57 seconds
Height reached by cat Ah = u²/2g
h = (7²)/(2 x 9.8)
h = 2.5 m
Speed of cat A before it hits the groundv = u + gt
v = 7 + 3(9.8)
v = 36.4 m/s
Speed of cat B before it hits the groundv = u + gt
v = 7 + 1.57(9.8)
v = 22.39 m/s
Time spent in air by cat A than cat B
Time difference = 3 s - 1.57 s = 1.43 seconds
Thus, the height reached by cat A is 2.5 m.
The speed of cat A before it hits the ground is 36.4 m/s.
The speed of cat B before it hits the ground is 22.39 m/s.
The time spent in air by cat A than cat B is 1.43 seconds.
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Different types of brain injuries and what they affect
Answer:
Explanation:
Traumatic brain injury (TBI) happens when a sudden, external, physical assault damages the brain. It is one of the most common causes of disability and death in adults. TBI is a broad term that describes a vast array of injuries that happen to the brain. The damage can be focal (confined to one area of the brain) or diffuse (happens in more than one area of the brain). The severity of a brain injury can range from a mild concussion to a severe injury that results in coma or even death.
Brain injury may happen in one of two ways:
CLOSE BRAIN INJURY : Closed brain injuries happen when there is a nonpenetrating injury to the brain with no break in the skull. A closed brain injury is caused by a rapid forward or backward movement and shaking of the brain inside the bony skull that results in bruising and tearing of brain tissue and blood vessels. Closed brain injuries are usually caused by car accidents, falls, and increasingly, in sports. Shaking a baby can also result in this type of injury (called shaken baby syndrome).
PENETRATING BRAIN INJURY: Penetrating, or open head injuries happen when there is a break in the skull, such as when a bullet pierces the brain.
DIFFUSE AXONAL INJURY: Is the shearing (tearing) of the brain's long connecting nerve fibers (axons) that happens when the brain is injured as it shifts and rotates inside the bony skull. DAI usually causes coma and injury to many different parts of the brain. The changes in the brain are often microscopic and may not be evident on computed tomography (CT scan) or magnetic resonance imaging (MRI) scans.
PRIMARY BRAIN INJURY: Refers to the sudden and profound injury to the brain that is considered to be more or less complete at the time of impact. This happens at the time of the car accident, gunshot wound, or fall.
SECONDARY BRAIN INJURY : Refers to the changes that evolve over a period of hours to days after the primary brain injury. It includes an entire series of steps or stages of cellular, chemical, tissue, or blood vessel changes in the brain that contribute to further destruction of brain tissue.
In his experiments on "cathode rays" during which he discovered the electron, J. J. Thomson showed that the same beam deflections resulted with tubes having cathodes made of different materials and containing various gases before evacuation.(b) When he applied various potential differences to the deflection plates and turned on the magnetic coils, alone or in combination with the deflection plates, Thomson observed that the fluorescent screen continued to show a single small glowing patch. Argue whether his observation is important.
The mobility of the light source depends on the interaction between the magnetic and electric forces.
What is a cathode ray?Cathode ray refers to the electron beam that moves from the negatively charged cathode to the positively charged anode at the other end of the vacuum tube.
J. J. Thomson demonstrated that the identical beam deflections produced tubes with cathodes composed of varied materials and containing a range of gases prior to evacuation.
This discovery is significant because the interaction of the magnetic and electric forces determines the mobility of the light source.
Therefore, the interaction of the magnetic and electric forces determines how mobile the light source is.
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A coin is rolled in a straight line along a balcony edge at a steady speed of 0.46 m/s.
a) Calculate how far the coin rolls in 2.4 s.
b) Another coin is dropped from the balcony. It accelerates from rest and hits the ground after
8.0 seconds at a speed of 78.4 m/s. Calculate the acceleration of the coin during its fall
answer:
Use this equation (v=Δx/t); plug in velocity (0.500 m/s) and the time (2.4 s), then solve for displacement… (Δx=1.2 m)
If a coin is rolled in a straight line along a balcony edge at a steady speed of 0.46 m / s , then the distance traveled by this coin in 2.4 seconds would be 1.104 meters.
What are the three equations of motion?There are three equations of motion given by Newton,
v = u + at
S = ut + 1/2×a×t²
v² - u² = 2×a×s
As given in the problem If a coin is rolled in a straight line along a balcony edge at a steady speed of 0.46 m / s ,
The distance traveled by the coin = 0.46 × 2.4
=1.104 meters per second
For another coin , by using the first equation of motion ,
v = u + a × t
78.8 = 0 + a × 8.0
a = 78.8 / 8.0
a = 9.85 m / s²
Thus, the distance traveled by this coin in 2.4 seconds would be 1.104 meters .
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An athlete is running a race. The athlete’s body needs energy. Which type of organelle in the athlete’s cells supplies the energy for cellular function?.
Mitochondria is a type of organelle in the athlete’s cells supplies the energy for cellular function.
Since mitochondria are the cellular organelles in charge of producing aerobic ATP, the "health" of mitochondria is crucial for proper cellular operation
Which organelles that give energy to the cell?Mitochondria. Dictionary Britannica, Inc. Mitochondria, or "powerhouses," are oval-shaped organelles that are present in the majority of eukaryotic cells. During cellular respiration, substances like glucose are converted by mitochondria into ATP, an energy molecule (adenosine triphosphate).
How Mitochondria produce ROS?The generation of ROS by mitochondria can result in oxidative damage to mitochondrial proteins, membranes, and DNA, impairing their capacity to synthesize ATP and perform a wide range of metabolic processes, including the tricarboxylic acid cycle, fatty acid oxidation, the urea cycle, amino acid metabolism, haem synthesis, and FeS center assembly, which are crucial to the normal functioning of most cells. The tendency of mitochondria to release intermembrane space proteins, such as cytochrome c (cyt c), to the cytosol by mitochondrial outer membrane permeabilization (MOMP), and so trigger the cell's apoptotic machinery, can also be increased by mitochondrial oxidative damage. The mitochondrial permeability transition pore (PTP), which opens up the inner membrane to tiny molecules in conditions like ischaemial reperfusion damage, is also induced by mitochondrial ROS generation. So it should come as no surprise that mitochondrial oxidative damage plays a role in a variety of diseases. Additionally, mitochondrial ROS may behave as a modifiable redox signal, impacting a number of activities in the mitochondria, cytosol, and nucleus in a reversible manner.
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A battery being tested has five cells testing normal and one cell showing very low. What action should be taken?
A. None, the battery is normal
B. Recharge the entire battery
C. Recharge only the cell that is very low
D. Replace the battery
The entire battery should be charged, as a battery being tested has five cells testing normal and one cell showing very low, so option B is correct.
What is Battery?A battery is a component that turns chemical energy into electrical energy and stores it. This process is called electrochemistry, and the structure that supports a battery is referred to as an electrochemical cell. One or more electrochemical cells can be used to create a battery, as in Volta's original pile. Two electrodes and an electrolyte are the main components of an electrochemical cell.
Some popular batteries are only intended for one usage (known as primary or disposable batteries). The electrons only travel in one direction from the anode to the cathode. Either the buildup of reaction products on the electrodes prevents the reaction from continuing, or their electrodes get depleted as they release their positive or negative ions into the electrolyte, and it is finished. The battery is eventually disposed of (or, ideally, recycled; however, that is a whole different Nova topic).
Therefore, the entire battery should be charged, as a battery being tested has five cells testing normal and one cell showing very low.
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A cubical surface surrounds a point charge q . Describe what happens to the total flux through the surface if (a) the charge is doubled,
According to Gauss law, the electric flux is defined as the electric field multiplied by the area of the surface in a plane perpendicular to the field.
Gauss law is defined mathematically in Equation 1
Φ=Q ϵo (1)
Where;
Q is enclosed charge
ϵo is the permittivity of the free space
According to the above gaussian relation, If the charge is doubled, then flux will also be doubled. This is because there is a direct relationship between the total flux and charge present in the electric field. This means that the net electric flux is dependent on the charge moving through the surface of the cube.
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The tank is 51m long and 20m wide.The sea water in the tank is 11m deep and has a density of 1030 kilograms per cubic meters.
Calculate the mass of water in the tank.
Answer: 1.2 x 10^7kg
Explanation:
Volume of tank = length x width x height
Volume = 51 x 20 x 11
Volume = 11220 m^3
Density = Mass/Volume
Density = 1030 kg/m^3
Volume = 11220 m^3
Mass = m
1030 = m/11220
m = 1030 x 11220
m = 11,556,600 kg or 1.2 x 10^7kg
if two 6-volt sources are connected in parallel to supply a 24-ohm load and the total current is 0.25 a, how much current would each source supply to the load? (round the final answer to three decimal places.)
V or total voltage is 6 volts because when multiple power supplies of the same voltage are connected in parallel, the applied voltage is same and the current equally divides between the number of power sources.
Divide I(t) or total current 0.25 amps between the two power sources.
Is=I(t)/Ns
Is=0.25amps/2sources
Is=.125amps
Voltage is the difference in electrical potential between two points.
Current is just the rate of flow of electric charge.
Each power source supplies .125amps of current to the load
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Consider this situation: A baseball travels upward and
rightward through the air. Of the forces listed, identify which
act upon the baseball.
Tap to select the forces that are present.
The forces acting on the baseball are air resistance, and force of gravity.
What are forces present during the upward motion of an object?
The forces which act on an object moving upward will either oppose the motion of the object or help to speed up the object.
The forces present during upward motion include;
force of air resistanceforce of gravityapplied forceThe forces acting on a baseball thrown upwards which also travels rightward include the following;
force of air resistance which oppose the upward motion of the baseballforce of gravity acting downwards due to the weight of the ball.Thus, the forces acting on the baseball are air resistance, and force of gravity.
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The complete question is below:
Consider this situation: A baseball travels upward and
rightward through the air. Of the forces listed, identify which
act upon the baseball. (force of air resistance, force of gravity, weight of the ball, frictional force).
On the basis of the repulsive nature of the force between like charges and the freedom of motion of charge within a conductor, explain why excess charge on an isolated conductor must reside on its surface.
Excess charge on an isolated conductor must reside on its surface because excess charge moves away until they reach the surface of the body.
Charged conductors in electrostatic equilibrium exhibit a number of interesting properties. The electric field beneath the surface of a charged conductor is zero when it is in electrostatic equilibrium, which is one of its properties. The repulsive nature of force between similar charges and the liberty of motion of charges within a conductor allows for the establishment of equilibrium within charges present in the conductor. Due to this fact, excess charges carry like type of charge as contained within the conductor they are thus repelled away from the conductor till they reach the outer surface of the conductor.
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A long, straight wire is surrounded by a hollow metal cylinder whose axis coincides with that of the wire. The wire has a charge per unit length of λ, and the cylinder has a net charge per unit length of 2λ . From this information, use Gauss's law to find (b) the charge per unit length on the outer surface of the
The charge per unit length on the outer surface is [tex]3\lambda[/tex]
Charge per unit length of the wire [tex]= {\lambda}[/tex].
Charge per unit length of the cylinder =[tex]{2\lambda}[/tex]
Gauss's law is a principle that connects the distribution of electric charge to the resulting electric field. In its integral form, it asserts that the flux of the electric field out of any closed surface, regardless of how that charge is distributed, is proportional to the electric charge enclosed by the surface.
The total charge per unit length of the cylinder is equal to the charge per unit length of the inner part of the cylinder plus the charge per unit length of the outer part:
Solve for [tex]{\lambda_{\text{out}}}[/tex] :
[tex]\lambda_{\text{out}}=2\lambda-\lambda_{\text{in}}[/tex]
Substitute for [tex]{\lambda_{\text{in}}}[/tex] :
[tex]\lambda_{\text{out}}&=2\lambda-(-\lambda)\\ &={3\lambda}}[/tex]
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You wish to start a fire by reflecting sunlight from a mirror onto some paper under a pile of wood. Which would be the best choice for the typeof mirror? (a) flat (b) concave (c) convex
You wish to start a fire by reflecting sunlight from a mirror onto some paper under a pile of wood which means the best choice of the type of mirror for this operation is a concave one and is denoted as option B.
What is Concave mirror?This type of mirror usually has a reflective surface that is curved inward and away from the light source. They also reflect light inward to one focal point which is done by reflecting all the rays parallel to its axis and converge them at a single point.
For fire to occur, then we need a large concentration of light rays which will help reflect all the sunlight from a mirror onto some paper under a pile of wood thereby causing the fire.
This is therefore the reason why concave mirror was chosen as the most appropriate choice.
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apply concepts what two forces are acting on the blocks as they slide over the wet sand? which one is a noncontact force?
Gravity is the non contact force.
What is a Gravity?Gravity is a fundamental interaction in physics that causes all objects with mass or energy to attract one another. The electromagnetic force, the weak interaction, and the strong interaction are all significantly stronger than gravity, which is by far the weakest of the four fundamental interactions. As a result, it has no appreciable impact on subatomic particle level phenomena. However, at the macroscopic level, gravity is the most important interaction between things and governs the motion of planets, stars, galaxies, and even light.
On Earth, gravitational pull lends weight to tangible objects, and the moon's gravitational pull generates ocean tides. In addition, gravity plays a significant role in many biological processes, including gravitropism, which directs plant growth, and the movement of fluids in multicellular organisms. Gravity may affect how the immune system and cells differentiate in the human body, according to research on the effects of weightlessness.
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find the velocity of a baseball thrown across a field a distance of 40 meters it takes the ball 4 seconds to cross the field
The velocity of a baseball thrown across a field is (V)= 10m/s
What is Velocity?Velocity of a particle is its speed and the direction in which it is moving.
It can also be described as the instantaneous rate of change of the particle's distance traveled.
How can we calculate the values of the velocity?To calculate the velocity we are using the formula here,
V= S/t
Here we are given,
S= a distance of a baseball thrown= 40m
t= time to travel the distance = 4 seconds.
Now we put the values in the above equation, we get
V= S/t
Or, V = 40/4
Or, V= 10m/s
So, from the above calculation we can conclude that, the velocity of a baseball thrown across a field is (V)= 10m/s
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A tennis ball is dropped from 1.98 m above
the ground. It rebounds to a height of 1.05 m.
The acceleration of gravity is 9.8 m/s².
With what velocity does it leave the ground?
The ball will leave the ground with the velocity of 4.5 m/s.
What is Velocity ?Velocity is the distance travelled in a specific direction per time taken. It is measured in m/s
Given that a tennis ball is dropped from 1.98 m above the ground. It rebounds to a height of 1.05 m. The acceleration of gravity is 9.8 m/s².
At maximum height, final velocity is zeroThe maximum height H = 1.05 mThe initial velocity u = 0Using the formula
v² = u² - 2gH
0 = u² - 2 × 9.8 × 1.05
u² = 20.58
u = √20.58
u = 4.54 m/s
Therefore, the ball will leave the ground with the velocity of 4.5 m/s.
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the sun is almost 400 times farther from earth than is the moon. how long does light from the moon take to reach earth?
About 1.3 seconds the light takes to reach from the moon to the earth.
How long does light from the moon take to reach earth?
We know that the closest object to our earth is the Moon. Its distance from the earth is about 240,000 miles, so light from the Moon takes 1 and 1/3 seconds to get from the Moon to Earth while on the other hand, sun is almost 400 times farther from earth as compared to the moon so the light reaches from sun is about 8 minutes 30 seconds.
So we can conclude that about 1.3 seconds the light takes to reach from the moon to the earth.
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a plastic rod that has been charged to − 15 nc touches a metal sphere. afterward, the rod's charge is − 1.0 nc .
According to the question a plastic rod that has been charged to − 15nc touches a metal sphere. Afterward, the rod's charge is − 1.0nc.The electrons will be transferred from the plastic rod to the metal sphere and the number of electrons ( n ) = 8.73 * 10^10
First of all, write the initial charge on the plastic rod, and then it touches the metallic sphere. Then, a few amounts of charge are transferred to the steel sphere. Later, calculating the price difference between the plastic rod and metal sphere, the kind of charged particle transferred may be decided. Ultimately, the number of electrons may be calculated by the use of the overall charge and the rate of the electron.
The expression of the total charge in electrostatics is Q = ne
Q = charge
n = number of electrons
e = charge of the electron
The initial charge on the plastic rod ( Qplastic ) = -15nC
Final charge on the metal sphere after it was touched by the plastic rod ( Qmetal ) = -1nC
The charge transferred from the metal rod to the sphere = ( Q = Qplastic - Qmetal )
Therefore Q = - 15nC - ( -1nC )
Q = -14nC
The plastic rod is negatively charged, so the electrons will be transferred to the metal sphere. The electrons will be transferred from the plastic rod to the metal sphere.
The expression of the total charge in electrostatics is Q = ne
The expression for n = Q / e
Q = -14nC
The charge on 1 electron = 1.602 * 10^-19 C.
Number of electrons ( n ) = -14nC ( 10^-9C/1nC ) / -1.602 * 10^-19 C.
Number of electrons ( n ) = 8.73 * 10^10
Threfore the number of electrons ( n ) = 8.73 * 10^10
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To win the game, a place kicker met kick a
football from a point 35 m (38.276 yd) from
the goal, and the ball must clear the crombar,
which is 3.05 m high. When kicked, the ball
leaves the ground with a speed of 20 m/s at
an angle of 45.9 from the horizontal.
The acceleration of gravity is 9.8 m/s²
By how much vertical distance does the ball
clear the crowbar?
Answer in units of m.
Answer:
2.08 m (2 d.p.)
Explanation:
Constant Acceleration Equations (SUVAT)
[tex]\boxed{\begin{array}{c}\begin{aligned}v&=u+at\\\\s&=ut+\dfrac{1}{2}at^2\\\\ s&=\left(\dfrac{u+v}{2}\right)t\\\\v^2&=u^2+2as\\\\s&=vt-\dfrac{1}{2}at^2\end{aligned}\end{array}} \quad \boxed{\begin{minipage}{4.6 cm}$s$ = displacement in m\\\\$u$ = initial velocity in ms$^{-1}$\\\\$v$ = final velocity in ms$^{-1}$\\\\$a$ = acceleration in ms$^{-2}$\\\\$t$ = time in s (seconds)\end{minipage}}[/tex]
When using SUVAT, assume the object is modeled as a particle and that acceleration is constant.
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When a body is projected through the air with initial speed (u), at an angle of θ to the horizontal, it will move along a curved path.
Therefore, trigonometry can be used to resolve the body's initial velocity into its vertical and horizontal components:
Horizontal component of u (x) = u cos θVertical component of u (y) = u sin θSince the projectile is modeled as moving only under the influence of gravity, the only acceleration the projectile will experience will be acceleration due to gravity.
If the ball is kicked at an initial velocity of 20 m/s from flat ground at an angle of 45.9° then:
Horizontal component of u = 20 cos 45.9°Vertical component of u = 20 sin 45.9° Resolving horizontallyThe horizontal component of velocity is constant, as there is no acceleration horizontally.
Resolving horizontally, taking → as positive:
[tex]s=35 \quad u=20 \cos 45.9^{\circ} \quad v = 20 \cos 45.9^{\circ} \quad a=0[/tex]
[tex]\begin{aligned}\textsf{Using} \quad s&=\left(\dfrac{u+v}{2}\right)t\\\\35&=\left(\dfrac{20 \cos 45.9^{\circ}+20 \cos 45.9^{\circ}}{2}\right)t\\35&=(20 \cos 45.9^{\circ})t\\t&=\dfrac{35}{20 \cos 45.9^{\circ}}\\\implies t&=2.51468288...\; \sf s\end{aligned}[/tex]
Therefore, the time is takes for the ball to reach the crossbar is 2.51 s.
Resolving verticallyAcceleration due to gravity = 9.8 ms⁻²
Resolving vertically, taking ↑ as positive:
[tex]u=20 \sin 45.9^{\circ} \quad a=-9.8 \quad t=2.51468288...[/tex]
[tex]\begin{aligned}\textsf{Using} \quad s&=ut+\dfrac{1}{2}at^2\\\\s&=(20 \sin 45.9^{\circ})(2.51468288...)+\dfrac{1}{2}(-9.8)(2.51468288...)^2\\s&=36.1171982...-30.9857870...\\\implies s&=5.131411132...\; \sf m\end{aligned}[/tex]
SolutionTo find by how much the ball clears the crossbar, subtract the height of the crossbar (3.05 m) from found the vertical height of the ball at 2.51 s:
[tex]\implies 5.13141132...-3.05=2.08\; \sf m\;(2 \: d.p.)[/tex]
Therefore, the ball clears the crossbar by 2.08 m (2 d.p.).
a proton, a deuteron and an a-particle are moving with same momentum in a uniform magnetic field. find ratio of their time period
The ratio of their time period is 1 : 2 : 2.
The momentum of a proton, a deuteron, and an alpha particle is the same in a uniform magnetic field.
The charge of a proton is q = e and the let m(p) be the mass of the proton.
Let m(d) = 2m(p) be the mass of the deuteron and the charge of a deuteron is q =e.
Now, an alpha particle is made up of 4 protons. Therefore the mass of an alpha particle is 4m(p) and the charge on an alpha particle is q = 2e.
The formula for the time period of a moving particle in a uniform magnetic field is given as:
[tex]T = \frac2 \pi m}{qB}[/tex] where B is the magnetic field, m is the mass and q is the charge of the particle.
So, the time period of a proton is:
[tex]T_{1} = \frac{2 \pi m(p)}{eB}[/tex]
The time period of a deuteron is:
[tex]T_{2} = \frac{2 \pi (2m(p))}{eB}[/tex]
And the time period of an alpha particle is:
[tex]T_{3} = \frac{2 \pi ( 4m(p) )}{2eB}[/tex]
Therefore, the ratio is:
[tex]T_{1}: T_{2} : T_{3} =\frac{2 \pi m(p)}{eB} : \frac{2 \pi 2m(p)}{eB} : \frac{2 \pi (4m(p))}{2eB}[/tex]
T₁ : T₂ : T₃ = 1 : 2 : 2
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HELP PLEASE IMMEDIATILY !!!!!!
- Determine the force required to accelerate a block of ice with a mass of 3.5 kg from 0 to 8 m/s2.
- Determine the acceleration that a cart with a mass of 25 kg experiences when it is being pulled with a force of 50 Newtons.
- Determine the mass of a block of ice that is accelerated to 6 m/s2 by a force of 3 Newtons.
- What is a free body diagram and what information does it contain?
Answer all of them please
The force required to accelerate the block is 28 N.
The acceleration of a cart with a mass of 25 kg and applied force of 50 N is 2 m/s².
The mass of a block of ice that is accelerated to 6 m/s2 by a force of 3 Newtons is 0.5kg.
A free body diagram is a sketch of forces acting on an object. It consists of the applied force, weight of the object, frictional force and normal reaction.
Force required to accelerate the blockThe force required to accelerate the block is calculated as follows;
F = ma
F = 3.5 kg x 8 m/s²
F = 28 N
Acceleration that cartThe acceleration of a cart with a mass of 25 kg and applied force of 50 N is calculated as follows;
a = F/m
a = 50/25
a = 2 m/s²
Mass of the block of iceThe mass of a block of ice that is accelerated to 6 m/s2 by a force of 3 Newtons is calculated as follows;
m = F/a
m = 3 N / 6 m/s²
m = 0.5 kg
What is a free body diagram?A free body diagram is a sketch of forces acting on an object. It consists of the applied force, weight of the object, frictional force and normal reaction.
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A toy doll and a toy robot are standing on a frictionless surface facing each other. The doll has a mass of 0. 20 kg, and the robot has a mass of 0. 30 kg. The robot pushes on the doll with a force of 0. 30 n. The magnitude of the acceleration of the robot is.
The magnitude of the acceleration of the robot is 1m/s^2 .
Given ,
A toy doll and a toy robot are standing on a frictionless surface facing each other .
The mass of the doll = 0.20kg
The mass of the robot = 0.30kg
Force applied by the robot on the doll = 0.30N
We know the force and mass of the robot , so from this we can calculate the acceleration by applying Newton's laws of motion ,
Thus , F= ma
a = F/m = 0.30N / 0.30k
a = 1 m/s^2
Hence , the magnitude of the acceleration of the robot is 1m/s^2 .
What is acceleration ?Acceleration is the rate of change in velocity.
Positive acceleration it occurs when an object speeds up. Negative acceleration it occurs when an object slows down.
Acceleration is a change of velocity over a period of time, expressed by the equation,
A=Δv/t
The unit of acceleration is m/s^2.
The dimensional formula of acceleration is [M^0 L^1 T^-2] .
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1ly/5.9 x 10^12 miles
Answer:
0.9964
Explanation:
I think that's the right answer but here you go always!
The concrete sections of a certain superhighway are designed to have a length of 25.0m . The sections are poured and cured at 10.0°C . What minimum spacing should the engineer leave between the sections to eliminate buckling if the concrete is to reach a temperature of 50.0°C ?
The minimum spacing the engineer should leave between the sections to eliminate buckling is 0.011 m.
To calculate the minimum space the engineer must leave in other to eliminate bulking, we use the coefficient of linear expansivity of steel.
What is coefficient of linear expansivity?This can be defined as the increase in length, per unit length, per degree rise in temperature.
To calculate the minimum space, we use the fomula below
Formula:
α = ΔL/L₁(t₂-t₁)........... Equation 1
Make L₂ the subject of the equation
ΔL = αL₁(t₂-t₁)........... Equation 2From the question,
Given:
L₁ = 25 mt₁ = 10°Ct₂ = 50°Cα = 11×10⁻⁶ /K ( Cofficient of Linear expansion of steel)Substitute these values into equation 2
ΔL = [11×10⁻⁶×25×(50-10)]ΔL = 0.011 mHence, the minimum spacing the engineer should leave between the sections to eliminate buckling is 0.011 m.
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pls help me!! 100 points!!!
"type a definition for each of the following words in YOUR own words."
1) Constants (also called Controls or Control Variables) –
2) Independent variable –
3) Dependent variable –
Answer:
1) Constants are variables that are kept the same throughout an experiment.
2) An independent variable is a variable that is manipulated by the experimenter.
3) A dependent variable is a variable that is measured by the experimenter.
Explanation:
the atoms of each element in a compound cannot be pulled apart
Answer:
Element of a compound typically cannot be separated by physical means because atoms are chemically bonded together
Explanation:
Compounds are substances composed of two or more elements chemically combined that can be separated into simpler substances only by chemical means
Consider (a) an electron (b) a photon, and (c) a proton, all moving in vacuum. Choose all correct answers for each question. (i) Which of the three possess rest energy?
Electron and proton have rest energy which is option (a) and (c) .
An electron is a solid negatively charged factor of an atom. Electrons exist outdoor of and surrounding the atom nucleus. Each electron includes one unit of bad charge (1.602 x 10^-19 coulomb)A proton is a subatomic particle discovered with inside the nucleus of each atom. The particle has a advantageous electric charge, identical and contrary to that of the electron A photon is a subatomic particle, having strength and momentum however no mass or electric powered charge, this is the quantum unit of electromagnetic radiation, together with light.According to Einstein's quantum theory light propagates in the form of packets i.e. quanta of energy, which is called photon.
The rest mass of photons is being zero. So photos do not have rest energy they are never at rest .
As electrons and protons posses mass , therefore they have rest energy which is given by [tex]E=mc^2[/tex] .
Hence , only electron and proton have rest energy not photon.
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