A block of mass 02kg is dropped from a height of 20 m from t
     A block of mass 0.2-kg is dropped from a height of 2.0 m (from the ground) onto a massless spring (the spring has an equilibrium length of 0.50 m). The block compresses the spring by an amount of 0.10 m by the time it comes to a stop. Calculate the spring constant of the spring.   
  
  Solution
>> Let Spring Constant of the spring = \'k\'
>> mass of block, m = 0.2 Kg
Let, Mass strikes the spring with velocity \'v\'
As, v = (2gh)1/2
>> and, h = 2 - 0.5 = 1.5 m
>> Now, Applying Energy Conservation at the point when it strikes spring & when it comes to rest
=> (1/2)mv2 + mgx = (1/2)kx2
From (1),
=> mgh + mgx = (1/2)kx2
As, h = 1.5 m
x = 0.1 m
m = 0.2 Kg
Putting all & Solving,
k = Spring Constant = 627.84 N/m ...ANSWER.

