Question

1. Two toboggans (with riders) of the same mass are at rest on top of a steep hill. As they slide down the hill, toboggan A takes a straight path down the slope while toboggan B winds back and forth along a more gently sloping path. Toboggan A makes the trip in one fourth the time of toboggan B.

(a)

Compare the work done by gravity on each toboggan.

Wg, A

Wg, B

=

(b)

Compare the average power delivered by gravity on the two toboggans.

Pg, A

Pg, B

=

2. While running, a person dissipates about 0.60 J of mechanical energy per step per kilogram of body mass. If a 58-kg person develops a power of 66 W during a race, how fast is the person running? (Assume a running step is 1.5 m long.)

Answer 1