Question

If stretch in a spring of force constant k is tripled then the ratio of elastic potential energy in the two cases will be:

Options

• 9 : 1

• 1 : 6

• 3 : 1

• 1 : 3

Answer 1

9 : 1

Explanation:

For a given spring, u = `1/2 "kx"^2`

∴ `"u"_2/"u"_1 = (1/2 "Kx"_2^2)/(1/2 "Kx"_1^2)`

= `(3"x")^2/"x"^2`

= 9 : 1