GPE to KE?

Question

The GPE at the top of the ramp is 1316.14 Joules and the KE at the bottom of the ramp is 1205.701901 Joules

What happened to the 110.438099 Joules. Was this energy lost through friction etc.

How would you calculate the frictional force to prove this.

Thanks, will give best answer.

Answer 1

k.e = kinetic energy = ½mv² = ½79(5.525)² = 1205.76 J



p.e = potential energy at ramp high = mgh = 79(9.81)1.7 = 1317.483 J



work-energy theorem:



net work = Δ k.e



=> 1317.483 + Ffrᵥᵥ = 1205.76



or Ffrᵥᵥ ~ = - 111.7 J



Ffr = frictional force = Ffrᵥᵥ / d = 111.7/10 ~ = 11.17 N



since Ffr and displacement are oppositely directed this energy is dissipated as heat energy in overcoming friction







hope this helps

Answer 2

We expect that this energy was lost to friction.

You cannot prove this by calculation.

Only if you could find a way to measure the frictional forces and the distance moved could you confirm that the missing energy was precisely consumed by friction.



Otherwise we simply take it to be true without further consideration.

Answer 3

The 110.4J is mechanical energy converted to heat by friction.



Work done by friction = force x distance

so

110.4 = F x ramp length



Solve for F.