Question

A small glider is placed against a compressed spring at the bottom of an air track that slopes upward at an angle of 38.0 ∘ above the horizontal. The glider has mass 6.00×10−2 kg . The spring has 630 N/m and negligible mass. When the spring is released, the glider travels a maximum distance of 1.40 m along the air track before sliding back down. Before reaching this maximum distance, the glider loses contact with the spring.

What is the kinetic energy of the glider .400m from the initial point against the compressed spring?

Answer 1

I used potential gravitational energy at 1.4m and at .4m, subtracting the energy to get KE, and came out with 0.36J

Answer 2

It was right