Angular Impulse-Momentum Principle - Example Problem 9.7-3

 

A 3-lb ball is attached to a spring and moves along a frictionless horizontal table under the influence of the force shown. The length of the spring and the speed of the ball in the transverse direction are represented in the graphs shown. Determine the force, as a function of time, if φ equals a constant 20 degrees.

 

 

Given:

• W = 3 lb
• φ = 20^o = constant

 

Find:

• F(t)

 

What is the radial position of the ball?

 

r = (4t/9) + 2 ft
r = (t/27) + (1/6) ft
r = (2t/3) + 4 ft