Physics Test 3 2015

A 400 N object is lifted vertically up 2.2m by a constant force. How much work is done by lifting this object?

880 J

A force of 15 N applied to a spring compresses it by 4 cm. What is the potential energy of the spring in the compressed position?

0.3 J

A .200 kg mass attached to the end of a spring causes it to stretch 5.0 cm. If .400 kg mass is added to the spring giving it a total of .600 kg, the potential energy of the spring will be

4 times as much.

An object hits a wall and bounce back with half of its original speed. What is the ratio of the final kinetic energy to the initial kinetic energy.

1/4

a 1.0 kg object moving in a certain direction has a kinetic energy of 2.0 J. It hits a wall and comes back with half its original speed. What is the kinetic energy of this object at this point.

.50 J

An object of mass 4 kg is thrown vertically upwards from ground level with an initial speed of 20 m/s. Ignore friction and use g = 10 m/s^2 . What is the kinetic energy of the object as it reaches its maximum height?

0 J

A 100 N force has a horizontal component of 80 N and a vertical component of 60 N. The force applied to a box which rest on a level frictionless floor. The cart starts from rest, and moves 2 m horizontally along the floor. What is the cart's final kinetic energy?

160 J

A motor is lifting a mass of 35 kg at a constant speed of 6 m/s. If friction is neglected, the power developed by the motor to do the lifting is

2.1 *10^3 W

An object is under the influence of a force as represented by the force vs. position graph as shown in figure 1. What is the work done as it moves from 0 to 4m?

20 J

An object is under the influence of a force as represented by the force vs. position graph as shown in figure 1. What is the work done as it moves from 4 to 6 m?

20 J

An object of mass 7.0 kg is dropped from a certain height. Just before it strikes the ground it has a kinetic energy of 1750 J. From what height was the object dropped? Ignore air resistance and use g= 10 m/s^2.

25m

An object is under the influence of a force as represented by the force vs. position graph as shown in figure 1. What is the work done as it moves from 6 to 12 m?

30 J

10-kg mass, hung onto a spring, causes the spring to stretch 2 cm. The spring constant is

4900

You and your friend [of the same mass] want to go to the EIffel Tower. Your friend takes the elevator straight up. You decide to walk up the spiral stairway, taking longer to do so. COmpare the gravitational potential [U] of you and your friend after you both reach the top.

Both of you have the same amount of potential energy.

At what point does the mass have the least potential energy?

C

At what point does the mass have the most kinetic energy?

C

Two men, Joel and Jerry push against a wall. Jerry stops after 10 min, while Joel is able to push for 5 min longer. Compare the work they do.

Neither of them do any work.

In the SI system of units, power has the same units as

Nm/s

You throw up a ball straight up. Compare the sign of the work done by gravity while the ball goes up with the sign of the work done by gravity while it goes down.

Work up is -, and the work down is +.

the work done by a conservative force between the two points is

always independent of the path.

As compared to Jack, Jill does twice the work in half the time. Jill's power output is

four times Jack's output.

An object is released from rest a height h above the ground. A second object with four times the mass of the first is released from the same height. The potential energy of the second object compared to the first is

four-times as much

If the net work done on an object is positive, then the object's kinetic energy

increases

If you double the speed of an object, its kinetic energy

is quadrupled

A force F pushes a block along a horizontal surface against a force of friction Ff. If the block undergoes a displacement s at constant velocity, the work done by the resultant force on the block

is zero

A constant force is applied to an object that causes a certain displacement. If the angle between the force and the displacement is 135 degrees, the work done by this force is

negative

Negative work means

the applied force is opposite to the displacement

The area under the curve on a Force-position [F-x] graph, represents

work

A 5 kg object slides down a frictionless surface inclined at an angle of 30 degrees from the horizontal. The total distance moved by the object along the plane is 10m. The work done on the object by the normal force of the surface is

zero

A body of mass m slides a distance d along a horizontal surface. How much work is done by gravity?

zero