Okay, got it now, thank you. So the energy at the highest point is the sum of KE + PE, which is (1/2)mv2 + mgh. Since v = 0 at the highest point, (1/2)mv^2 = 0. So kinetic energy is zero (obviously, since we aren't moving). So the total energy (which is conserved on frictionless track) is equal...
(2) Another attempt... PE(spring) = PE = (1/2)mx2 ==> (1/2)(900)(0.088^2) = 3.4848. Plugging this value of PE into PE = (1/2)mv2, I get V(initial) = 4.82. Plugging this into (1/2)mV^2 = (1/2)mV^2 + mgh, I get that the velocity at the top of the ramp = 3.92 m/s. Is this sensible?
Homework Statement
A toy car of mass 0.300 kg is shot out of a compressed horizontal spring (A), and then travels around a loop-the-loop along a frictionless track. The spring has a spring constant k = 900 N/m, and 3.50 J of energy was stored in the spring by compressing it.
(1) How far was...