Question

a spring of force constant 800N/m has an extension of 5cm .The work done in extending it from 5cm to 15cm is

Answer 1

PE energy stored initially -1/2kx^2 ,, k= 800 , X= 0.05 m

PE in second case -1/2kx^2. ,, X = 0.15

subtract. second from 1st equation

( and it is hard to type from moving bus ,, thus it took time and I can't explained it in detail )