A tower crane is lifting a 10,000 lb object B at a constant rate of 7 ft/s while rotating...

A tower crane is lifting a 10,000 lb object B at a constant rate of 7 ft/s while rotating at a constant rate of rad/s. In addition, B is moving outward with a radial velocity of 1.5 ft/s. Assume that the object B does not swing relative to the crane (i.e., it always hangs vertically) and that the crane is fixed to the ground at O.

(a) Determine the radial velocity required of the 20 ton counterweight A to prevent the horizontal motion of the system’s center of mass.

(b) Find the total force acting on A and on B.

(c) Determine the velocity and acceleration of the mass center of the system when A moves as determined in Part (a).

Figure P5.39