The motion of a 4-lb block B in a horizontal plane is defined by the relations r = 3t 2- t...

The motion of a 4-lb block B in a horizontal plane is defined by the relations r = 3t 2- t 3 and θ=2t2, where r is expressed in feet, t in seconds, and θ in radians. Determine the radial and transverse components of the force exerted on the block when (a) t = 0, (b) t = 1 s.

Fig. P12.68