A block of mass 4 kg while at rest is attached to an unstretched spring. The force constant of spring is `24 Nm^(-1)`. If a constant horizontal force of 10 N is applied on the block, the spring gets compressed by 0.5m. What is the speed of the block at this point?

Explanation

Given : `k = 24 N m^(-1) m = 4 kg, S = 0.5 m` work done by the applied force provides kinetic energy to mass and elastic potential energy to the spring.  
`:. 10 xx 0.5 = (1/2 xx 4 xx v^2) + [1/2 xx 24 xx (0.5)^2]`
or `5 = 2v^2 + 3 or 2v^2 = 2`
or `v = 1 ms^(-1)`
Speed of the block = `1 ms^(-1)` .