Work and Kinetic Energy
Work Energy Theorem
Potential Energy
Conservation of Energy
Potpourri
100
How much work is done lifting a 40 newton block 2 meters?
80 joules
100
Which of the following is true of a 1 kg mass and a 5 kg mass that both fall from rest from the same height?
A) the force felt due to gravity is the same on both masses
B) their initial potential energies are equal
C) they lose potential energy at the same rate
D) they have the same kinetic energy upon hitting the ground
E) their accelerations are equal
E) their accelerations are equal
100
Which of the following statements concerning a skier in a valley is true if friction and air resistance are negligible?
I. The skiers speed is maximum at the bottom of the valley
II. The skiers speed is at a minimum at the top of the valley
III. The skiers potential energy is zero at the top of the valley
A) I only B) II only
C) I and II only D) II and III only
E) I, II and III
C) I and II only
100
A student throws a stone upward at an angle of 30°. Which statement best describes the stone at the highest point that it reaches?
A) Its acceleration is zero.
B) Its acceleration is at a maximum.
C) Its potential energy is at a minimum.
D) Its kinetic energy is at a minimum.
E) Its potential and kinetic energies are equal
D) Its kinetic energy is at a minimum.
100
A roller coaster car starts at Point A and travels along a frictionless slope traveling to Point E which is at a slightly lower height.
"
The car's speed is the fastest at which point?
C
200
In order to demonstrate some concepts of physics, a physics teacher pushes against a wall with a force of 300 N for 5 s. As you can imagine, the wall remains stationary. How much work does the teacher do on the wall in this time period?
OJ
200
Two balls of equal size are dropped from the same height from the roof of a building. One ball has mass M and the other has a mass 2M. When the balls reach the ground, how do the kinetic energies of the two balls compare? (Neglect friction)
A) M has one-fourth the kinetic energy of 2M.
B) M has one-half the kinetic energy of 2M.
C) M has the same amount of kinetic energy as 2M.
D) M has twice the amount of kinetic energy as 2M.
E) M has four times the amount of kinetic energy as 2M.
B) M has one-half the kinetic energy of 2M.
200
5 kg bowling ball in a pendulum assembly is given an initial velocity of 10 m/s. What is the maximum height reached by the ball?
5 meters
200
A block of mass m is attached to a placed on a vertical spring with force constant k. If the spring is depressed a distance x, what is maximum height reached by the block?
A)
B)
C)
D)
E)
A)
200
An object with a mass of 2 kg is attached to the end of a 3 m long string and is whirled horizontally in a circle with a constant speed of 5 m/s. When the object has traveled half a revolution, how much work has been done by the centripetal force?
0J
300
A horizontal force of 40 N is used to push a block along a horizontal surface at a constant speed of 2 meters per second. How much work is done on the block in 6 seconds?
480 J
300
An object at rest weighs 100 N on earth. It gains 100 J of kinetic energy. What is its velocity?
4.47m/s
300
Which of the following is true of the energy of a spring-mass system?
A) The total energy is greatest when the velocity is greatest.
B) The total energy is greatest when the displacement is greatest.
C) The potential energy is greatest when the displacement is least.
D) The kinetic energy is greatest when the potential energy is least.
E) The total energy varies based on the position of the mass.
D) The kinetic energy is greatest when the potential energy is least.
300
If an object of mass 5 kg is released from rest at the beginning of the track, what is its velocity at point D?
2m/s
300
A vertical force of 500 N acts on a 12 kg mass over a horizontal displacement of 2 m. The work done by the force is
A) 0 J
B) 24 J
C) 1000 J
D) 6000 J
E) 12000 J
A) 0 J
400
How much work is done by friction if a 20 kg block sliding at 10 m/s is slowed down to 4m/s?
840 joules
400
If a 5,000 kg runaway truck is traveling 30 m/s, how high must a ramp be to bring the truck to a complete stop?
45m
400
A pendulum of mass m on a massless string of length l is displaced an angle . What is the maximum velocity of the pendulum?
A) 
B) 
C) 
D) 
E) 
A)
400
A student drops a 0.02 N coin from a 4 meter high window onto a spring with a constant of 0.01 N/cm. How far is the spring depressed? Neglect air resistance.
4 cm
400
A woman pushes a lawn mower with a force of F at an angle to the ground. If F = 20N and = 30°, what is the net work done in moving the lawnmower 5m?
86.67J
500
If L, M and T denote the dimensions of length, mass, and time, respectively, what are the dimensions of energy?
A) M/T2
B) ML/T2
C) ML2/T2
D) M/L2
E) T2/M
C) ML2/T2
500
Just before hitting a nail, a 2 kg hammer is moving at 10 m/s just before it hits a nail. If the wood exerts a constant 180 newton force on the nail, how far does the nail go?
0.6m
500
A 3 kg object is dropped from a height of 4 m onto a spring. The maximum compression of the spring is 0.5 m. What is the spring constant?
960 N/m
500
A 4.0 kg block rests at the edge of a platform that is 20 m above level ground. The block is launched horizontally with an initial velocity of 15 m/s.
What is the object's kinetic energy when it hits the ground?
1250J
500
Of the following, which is NOT a unit of power?
A) Watt
B) Joule per second
C) Kilogram meter squared per second cubed
D) Kilowatt-hour
D) Kilowatt-hour