A spring has a force constant of 70000 N/m.

How far must it be stretched for its potential energy to be 21 J?

1 answer

well, let's see. You are only given two pieces of data, so the manipulation must be simple.

energy(N-m) = N/m * m^2

P.E. = 1/2 kx^2
21 = 1/2 (70000)x^2
x^2 = .0006
x = .0245m or 2.45 cm