Question

If it requires 9.0 j of work to stretch a particular spring by 2.0 cm from its equilibrium length, how much more work will be required to stretch it an additional 4.0 cm?

Answer 1

As we know that work done to stretch the spring will be given as

`U = (1)/(2)kx^2`

so here we have

`9 = (1)/(2)k(0.02)^2`

so we have

`k = 45000 N/m`

now we need to find the work done to stretch the spring from x = 2 cm to x = 4 cm

here we have

`U = (1)/(2)k(x_1^2 - x_2^2)`

now we have

`U = (1)/(2)(45000)(0.06^2 - 0.02^2)`

`U = 72 J`