Work-Energy Theorem – AP Physics 1

1. A 10 N force moves a 2 kg block 5 m horizontally (no friction). The final KE is:

100 J 50 J 25 J 10 J

2. A force is applied at 60° above horizontal. The work done per meter is F × :

sin 60° = 0.87 cos 60° = 0.50 tan 60° = 1.73 1 (no reduction)

3. Why does the normal force do zero work on a horizontally moving object?

Normal force is always zero It acts perpendicular to displacement Normal force cancels friction It acts in the same direction as motion