### Converting to GPE to KE with 83% loss

My ongoing efforts to show that gravitational potential energy can be converted to kinetic energy remains plagued by seriously high losses. This term I was armed with a level to ensure that the horizontal plumb line was horizontal.

I started from this pillar on the sidewalk.

I rode down this slope, a drop of 0.4 meters. With my mass plus the mass of the RipStik being 71.2 kg, the GPE was 71.2 kg × 9.79 m/s² × 0.4 m = 278.8 Joules.

At this intersection ahead I took a right turn and used the corner post and next post to obtain my velocity (from the woman in yellow to the women in white). That distance was 1.06 meters and I covered it in 0.94 seconds for a speed of 1.13 m/s.

This photo was taken during a second ride down slope, here I am on the 1.06 meter timed distance stretch, this is level terrain. Slowing is obviously an issue here.

My kinetic energy was 0.5 × 71.2 kg × (1.13 m/s)² = 45.5 Joules. That is only 16% of the energy provided by GPE. Conservation of energy was not well shown, but the attempt was sure fun. The image above shows the timed distance stretch, the level and surveyor's line can also be seen.