Work and Kinetic Emergy Physics quiz

A car of mass, M, is traveling along a flat smooth stretch of road when it is forced to make a sudden stop. The cards skids a distance D before coming to rest. If the car is traveling twice as fast the distance it would travel before coming to rest would be

four times the distance

A 1000 W electric motor lifts a 100 kg safe at constant velocity. The vertical distance through which the motor can raise the safe in 10 s is most nearly

10 m

A box of mass M is slid up an incline at an angle theta. How much work is done if the box is slid to the top of the ramp, a height H off the ground.

MgH

An object is dropped from rest from a certain height. Air resistance is negligible.

After falling a distance d, the object's kinetic energy is proportional to which of the following?

d

A softball player catches a ball of mass m, which is moving towards her with horizontal speed V. While bringing the ball to rest, her hand moved back a distance d. Assuming constant deceleration, the horizontal force exerted on the ball by the hand is

mV²/(2d)

A force F at an angle theta above the horizontal is used to pull a heavy suitcase of weight mg a distance d along a level floor at constant velocity. The coefficient of friction between the floor and the suitcase is mew. The work done by the frictional force is:

-Fd(cos(theta))

A variable force acts on an object as shown above. How much work is done from

position x = 2m to position x = 6m?

120 Nm

The following graphs, all drawn to the same scale, represent the net force F as a function of displacement x for an object that moves along a straight line. Which graph represents the force that will cause the greatest change in the kinetic energy of the object from × = 0

to x = x1?

D

A child pushes horizontally on a box of mass m which moves with constant speed v across a horizontal floor. The coefficient of friction between the box and the floor is mew. At what rate does the child do work on the box?

(mew)mgv

From the top of a high cliff, a ball is thrown horizontally with initial speed Vo. Which of the following graphs best represents the ball's kinetic energy K as a function of time t ?

D