Question

plz help me out with this​

Answer 1

It requires 4 J of work

1/2 k x^2 = 4

As potential energy = 1/2 kx^2

x= 10 cm = 0.1m

So

1/2 k ( 0.1)^2 = 4

k= 8/0.01 = 800 N/m

Extra work to stretch it through additional 10 cm

1/2 k ( 20^2 - 10^2)/10000

1/2 × 800( 400 - 100)/10000

400 × 300× 1/10000

12J