Work CHAPTER -9

.5 Force, Work, and Potential Energy

.6 Finding Force from Potential Energy

15. A particle moves in a vertical plane along a closed path, starting at A and eventually returning to its starting point. How much work is done on the particle by gravity? Explain.

A

16. a. If the force on a particle at some point in space is zero, must its potential energy also be zero at that point? Explain.

b. If the potential energy of a particle at some point in space is zero, must the force on it also be zero at that point? Explain.

17. The graph shows the potential-energy curve of a  Energy particle moving along the x-axis under the influence of a conservative force.

a. In which intervals of x is the force on the particle
to the right?

x (m)

b. In which intervals of x is the force on the particle
to the left?

c. At what value or values of x is the magnitude of the force a maximum?

.

11-10 CHAPTER 11 Work

d. What value or values of x are positions of stable equilibrium?

e. What value or values of x are positions of unstable equilibrium?

f. If the particle is released from rest at x = 0 m, will it reach x = 10 m? Explain.

.7 Thermal Energy

1               A car traveling at 60 mph slams on its brakes and skids to a halt. What happened to the kinetic energy the car had just before stopping?

2               What energy transformations occur as a skier glides down a gentle slope at constant speed?