Identify each situation as: WORK IS DONE or WORK IS NOT DONE           a.A teacher applies force to a wall and becomes exhausted.           b.A book falls off the table to the ground.           c.A rocket accelerates through space

Which of the statements below is true when you catch a baseball that comes at you horizontally?   a. The work that you do is positive.     b. The work that you do is negative.   c. Work is not a vector and cannot be referred to as positive or negative.       d. Work is a scalar product expressed in terms of magnitudes, so it is never negative.     e. Work is expressed in terms of kinetic energy, which must be positive.

4. Identify a case where an object is moving over a surface with friction, but the frictional force does no work.

You lift your backpack from the ground and moved forward to your car. Which of the following statements is true? A. Work is done on the backpack while lifting it and moving it forward. B. Work is done on the backpack while lifting it and but not when moving it forward. C. No work is done on the backpack while lifting it but work is done on it when moving it forward. D. No work is done on the backpack at all.

Choose all the correct statement that applies to Work.   A. Work is the product of force and distance.   B. Work is a vector quantity.   C. Work is a scalar quantity.   D. work has magnitude only.

The unit of work, joule, is dimensionally the same as: a. Newton‑meter    b. Newton/kilogram.                      c. kg•m2/s2            d. a and c               e. a and b                                     f. b and c

Two balls having different masses reach the same height when shot into the air from the ground. If there is no air drag, which of the following statements must be true? (More than one statement may be true.) A. Both balls left the ground with the same speed. B. Both balls left the ground with the same kinetic energy. C. Both balls will have the same gravitational potential energy at the highest point. D. The heavier ball must have left the ground with a greater speed than the lighter ball. E. Both balls have no acceleration at their highest point.

2. A boy pulls a 26.0-kg box with a 170-N force at 38° above a horizontal surface. If the coefficient of kinetic friction between the box and the horizontal surface is 0.18 and the box is pulled a distance of 28.0 is the net work done on the box? J 16 cct il6 cci16 what 091103 5 cci16 cei cei16

7. A force of 180 N stretches a spring 0.050 m beyond its unstretched length. a. What is the spring constant of this spring? b. What magnitude of force is needed to stretch the spring 0.012 m beyond its unstretched length? C. How much work must be done to stretch the spring 0.012 m beyond its unstretched length? d. What magnitude of force is needed to compress the spring 0.025 m? e. How much work must be done to compress the spring 0.025 m?

A box sits on the horizontal bed of a truck that is accelerating to the left, as shown in the diagram. Static friction between the box and the truck keeps the box from sliding around as the truck accelerates. The work done on the box by the static friction force as the accelerating truck moves a distance D  to the left is A. Positive B. Zero C. Negative D. Dependent upon the speed of the truck