A uniform light spring has unstretched length of 3.0 m. One of its end is fixed to a wall. A particle of mass m = 20 g is glued to the spring at a point 1.0 m away from its fixed end. The free end of the spring is pulled away from the wall at a constant speed of 5 cm/s. Assume that the spring remains horizontal (i.e., neglect gravity). Force constant of spring = 0.6 N / cm.
(a) With what speed does the particle of mass m move?
(b) Find the force applied by the external agent pulling the spring at time 2.0 s after he started pulling.

Answer

(a) `(5)/(3) cms^(-1)`
6N