1. A ball is projected up an incline and rolls around a track as shown above. At which two labelled points is the work done by the gravitational force on the ball not negative? Select two answers. 2. A single force is exerted on an object in the x
direction. Shown is a graph of that force and the displacement of the object in that direction. What amount of work is done for the 30 m shown?
a. 30J
b. 45J
c. 50J
d. 60J

3. An object of mass, m, hanging from the end of a
light string is initially at rest. It is lowered by the string a distance s and reaches a speed vf. How much work was done on the object by the string?

A single constant force is exerted on an object. The graph describes the object's energy. How much work was done to increase the speed of the object from 1.0 m/s to 3.0 m/s?
A. 1.5J
B. 2.0J
C. 4.0J
D. 4.5 J

5. A block of mass m initially at rest is pulled along
a plane inclined at 30° with the horizontal. At a height h it has kinetic energy Kf. The coefficient of friction with the incline is J. Which of the following correctly represents the net work done on the block?

An object of mass, mn, is attached to a spring hanging from the ceiling as shown. It is initially sup ported so the spring is unstretched. The object is released and falls. Which of the following correctly describes the kinetic energy of the object when it has fallen a distance h below the starting point?