3/122 The collar has a mass of 2 kg and is attached to the light spring, which has a stiffness of 30 N/m and an unstretched length of 1.5 m. The collar is released from rest at A and slides up the smooth rod under the action of the constant 50‐N force. Calculate the velocity v of the collar as it passes position B.

Explanation:

According to the law of conservation of energy, work done by the force is as follows.

                   = 64.95 J

Now, gain in potential energy is as follows.

                P.E = mgh

                      =

                      = 29.4 J

Gain in potential energy will be as follows.

           =

           =

           = 11.25

As,

                   = 64.95 J - 29.4 - 11.25

                   = 24.3

                  v = 4.92 m/s

Therefore, we can conclude that relative velocity at point B is 4.92 m/s.