A spring has a force constant of 40000 N/m. How far must it be stretched for its potential energy to be 42 J?
Answer in units of m

0.05m

Explanation:

Given parameters:

Force constant of the spring  = 40000N/m

Potential energy  = 42J

Unknown:

Extension  = ?

Solution:

To solve this problem, use the expression below:

           E.PE  = k e²  

k is spring constant

e is the extension

              42  =    x 40000 x e²  

               e  = 0.05m