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Practice Test Mechanical Energy |
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Assume magic land conditions on all problems unless stated otherwise. In
other words there is no air resistance or friction. |
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Indicate the best answer: |
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1 |
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Bill throws a rock straight up at a velocity = 10 m/s. How high does it go? |
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2 |
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A cannon ball has a velocity of 220 m/s. It falls to earth and has a
velocity of 200 m/s just before it hits. What % of the energy was lost as
heat? |
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A 200 kg motorcycle traveling at 20 m/s and suddenly speeds up to 30 m/s.
How much work was done? |
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4 |
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Find the minimum power required for a person to drive a car at a constant
speed of 30.0 m/s up a 30 degree slope. Assume the mass of the person and
car = 1000 kg |
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5 |
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A box of mass m sits on top of a nonlinear spring which is compressed below
its equilibrium point by a distance x. How high will the box go when it is
released? The spring's equation is: F = kx^3. |
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6 |
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How much work does the gravity of a planet do on a satellite as it orbits ? |
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7 |
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Superman pushes on a box with force of 1000 Newtons. His force makes an
angle of 60 degrees with the horizon. The box moves 5 meters at a constant
velocity of 40 m/s. How much work is done by the friction force acting on
the box. Assume no air resistance force. |
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For a non linear spring Us = 7 x^3 +2x^2. Find an expression for the force
as a function of x. |
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A nonlinear spring has the following relationship between force and
displacement of the spring from its equilibrium: F = -3 x^3 - 2 x^2 - 3x.
Find the amount of energy stored in the spring if it is compressed by 2
meter. |
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10 |
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Jane attaches an unknown mass to a linear spring with a spring constant k.
She measure the period of the spring and mass system a time = T. What is
the mass of the meteor? |
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11 |
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Two large wheels move down equal slopes. One has friction and the other
doesn't. Which wheel has the highest linear velocity at the bottom? |
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12 |
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A force 6i, 7j, -2k pushes on a mass and displaces it an amount 2i, -3j, 4k.
What is the change in kinetic energy for the mass? |
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13 |
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A pendulum has a velocity of v at its lowest point. How high will it swing
up in the vertical dimension? |
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14 |
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Bob throws a rock with a mass of m off a cliff of height = h. What is the
velocity of the rock just before it hits the ground? |
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Robin Hood fires his bow straight up to a height = h. He then fires it at a
30 degree angle with respect to the horizontal. How high does it go? |
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A box slides a vertical distance = h down a 29 degree slope. At the bottom
it has a velocity of ( 0.64 gh )^0.5. How much energy was dissipated as
heat? |
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Bob is driving his scooter at 20 m/s and slows down to 10 m/s over a 5
second period. How much mechanical energy was converted to heat? |
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