Help With Spring Constants and Oscillaions

[alexito01]

Homework Statement

A toy car with mass 0.02 kg is propelled by a spring with a spring constant 80 N/m onto a track. The track. The track contains a loop of radius 0.10m. Ignore any losses dueto friction and use g=10m/s. What is the minimum compression of the spring necessary for the car to complete the loop without leaving the track?

Homework Equations

ω=√k/m x=mg/k T=2π/ω V_t = rω

The Attempt at a Solution

 

[Mthees08]

Hint: Use energy