An 8 lbm box is moving around the circle of radius rA = 2 ft with a speed of vA = 5 ft/s while connected to the end of the rope. Just after (not before) the box passes point A, the rope is pulled with a constant inward speed of 4 ft/s.
a) Calculate the total velocity of the box at the instant it reaches point B.
b) Calculate the amount of work done from A to B assuming friction is negligible.