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3 years ago

Diagram B D c с Which car has: Ke = 100 PE=0? * 1 point A B C D

Physics

1 answer:

erma4kov [3.2K]3 years ago

6 0

Answer:

The car C has KE = 100, PE = 0

Explanation:

The principle of conservation of energy states that although energy can be transformed from one form to another, the total energy of the given system remains unchanged.

The energy that a body possesses due to its motion or position is known as mechanical energy. There are two kinds of mechanical energy: kinetic energy, KE and potential energy, PE.

Kinetic energy is the energy that a body possesses due to its motion.

Potential energy is the energy a body possesses due to its position.

From the principle of conservation of energy, kinetic energy can be transformed into potential energy and vice versa, but in all cases the energy is conserved or constant.

In the diagram above, the cars at various positions of rest or motion are transforming the various forms of mechanical energy, but the total energy is conserved at every point. At the point A, energy is all potential, at B, it is partly potential partly kinetic energy, However, at the point C, all the potential energy has been converted to kinetic energy. At D, some of the kinetic energy has been converted to potential energy as the car climbs up the hill.

Therefore, the car C has KE = 100, PE = 0

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Block with mass m =7.6 kg is hung from a vertical spring. when the mass hangs in equilibrium, the spring stretches x = 0.29 m. w

PSYCHO15rus [73]

1) 256.9 N/m

The force applied to the spring is equal to the weight of the block hanging on the spring:

$F=mg=(7.6 kg)(9.8 m/s^2)=74.5 N$

And the spring constant can be found by using Hook's law, because we know that the displacement caused by this force is x = 0.29 m:

$F=kx\\k=\frac{F}{x}=\frac{74.5 N}{0.29 m}=256.9 N/m$

2) 1.08 Hz

The angular frequency of oscillation of the spring is given by the formula:

$\omega=\sqrt{\frac{k}{m}}=\sqrt{\frac{256.9 N/m}{7.6 kg}}=5.81 rad/s$

And the frequency of oscillation is given by:

$\omega=2\pi f\\f=\frac{2 \pi}{\omega}=\frac{2\pi}{5.81 rad/s}=1.08 Hz$

3) 2.19 m/s

The velocity at time t of the block is given by:

$v=v_0 cos (\omega t)$

where

$v_0 = 4.4 m/s$ is the initial velocity of the block

$\omega=5.81 rad/s$ is the angular frequency

t is the time

Substituting t=0.36 s, we find the speed of the block at that time:

$v(0.36 s)=(4.4 m/s) ( cos ((5.81 rad/s)(0.36 s)) = -2.18 m/s$

And the negative sign means that the direction of the velocity is upward (because the initial velocity was downward)

4) 25.6 m/s^2

The maximum acceleration is given by:

$a_0 = \omega^2 A$

where A is the amplitude of the oscillation.

We can find the amplitude by using the law of conservation of energy: in fact, the kinetic energy at the equilibrium point must be equal to the elastic potential energy at the point of maximum displacement:

$K=U\\\frac{1}{2}mv_0^2 = \frac{1}{2}kA^2\\A=\sqrt{\frac{mv_0^2}{k}}=\sqrt{\frac{(7.6 kg)(4.4 m/s)^2}{256.9 N/m}}=0.76 m$

So, the maximum acceleration is

$a_0 = \omega^2 A=(5.81 rad/s)^2 (0.76 m)=25.6 m/s^2$

5) 95.1 N

The magnitude of the net force acting on the block is given by the difference between the weight and the restoring force of the spring:

$F=mg-kx$

First, we need to find the position x at t=0.36 s, which is given by

$x(t)=A sin(\omega t)=(0.76 m)(sin ((5.81 rad/s)(0.36 s))=0.66 m$

And so, the net force is

$F=(7.6 kg)(9.8 m/s^2)-(256.9 N/m)(0.66 m)=-95.1 N$

And the negative sign means the direction of the force is upward.

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3 years ago

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Relate a car's suspension to harmonic motion

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Relating a car homones

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3 years ago

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1) An average soccer ball has a mass of .4 kg. If a soccer ball is kicked with a force of 750 Newtons, what is the acceleration

Y_Kistochka [10]

Answer:

Explanation:

#1 uses Newton's 2nd Law: F = ma so filling in:

750 = .4a and

a = 1875 m/s/s

#2 uses d = rt so

d = 12.3(25) and

d = 307.5 m

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3 years ago

Why does a straw look broken viewed in a glass of water?

Nat2105 [25]

Answer:

This is due to refraction of light

Explanation:

When a straw is placed in a glass it appears to be broken as a result of refraction of light on the air-water interface.

Since, the refractive index of water is more than that of glass.

Also, water is denser than air, which means light travels slower in water than in air.

Most importantly, When light travels from rarer to denser medium it bents towards the normal and deviates from its original path which explains the broken view of straw in a glass of water.

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4 years ago

2. How long will it take for a ball thrown vertically upward with an initial velocity of

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Answer:

13.33 seconds

Explanation:

At maximum height, the equation of motion becomes:

v = u + at

Since the object was thrown vertically, the initial velocity (u) is zero and the acceleration (a) becomes the acceleration due to gravity (10 m/s2). The equation becomes:

v = at

v = 480 km/hr = 133.333 m/s

10t = 133.333

t = 133.333/10

t = 13.33 seconds.

The time for the ball thrown vertically with a velocity of 480 km/hr to reach the maximum height is 13.33 seconds.

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3 years ago

Diagram B D c с Which car has: Ke = 100 PE=0? * 1 point A B C D​

Diagram B D c с Which car has: Ke = 100 PE=0? * 1 point A B C D