Question

2. A spring launcher has a spring with a spring constant of 675N / m A child wants to launch a 0.15 kg rock 3.0 m vertically into the air . How far back does the child have to pull the rock back before releasing it?

Answer 1

Below

Step-by-step explanation:

The Elastic Potential Energy of the spring , 1/2 k x^2 , will need to equal the potential energy of the rock at 3m ( mgh)

1/2 k x^2 = mgh where x is the distance the child pulls

1/2 (675 N/m) x^2 = .15 kg (9.81 m/s^2)(3 m)

1/2 (675) x^2 = 9.81 (3)(.15)

x=.114 m = 11.4 cm