A variable force of magnitude F(x) moves a body of mass m along the x-axis from x1 to x2. The net work done by the force in moving the body from x1 to x2 is where v1 and v2 are the body's velocities at x1 and x2. Knowing that the work done by the force equals the change in the body's kinetic energy, solve the problem.A 2-oz tennis ball was served at 130 ft/sec about (89 mph). How much work was done on the ball to make it go this fast? (To find the ball's mass from its weight, express the weight in pounds and divide by 32 ft/sec2, the acceleration of gravity.)

Question

A. 31 ft-lb
B. 33 ft-lb
C. 66 ft-lb
D. 15 ft-lb

Answer 1

Answer: B