# Physics

posted by
**Jarin**
.

Jack rides his 213kg motor cross bike 25.3m up a 30.0 degree slope at a constant speed. what is the energy his bike expends if the frictional force opposing its movement is one-tenth its weight?

Are you sure the mass is 213 kg? Shouldn't it be 21.3 kg? Or does that include Jack's own mass? Eithner way, 213 kg seems too hign.

The work is expended by the bike rider, not the bike itself.

The actual work done, including frictional work, is the weight times the vertical diatance change (25.3 sin 30) PLUS the frictional force times the distance moved.

Sorry, I assumed this was a bicycle. It is apparently a motor vehicle. The method of solution remains what I outlined, but the 213 kg should include the weight of the rider