In the sport of skeleton a participant jumps onto a sled (known as a skeleton) a
ID: 1556612 • Letter: I
Question
In the sport of skeleton a participant jumps onto a sled (known as a skeleton) and proceeds to slide down an icy track, belly down and head first. The track has sixteen turns and drops 122 m in elevation from top to bottom.
(a) In the absence of nonconservative forces, such as friction and air resistance, what would be the speed of a rider at the bottom of the track? Assume that the speed at the beginning of the run is relatively small and can be ignored.
m/s
(b) In reality, the best riders reach the bottom with a speed of 35.8 m/s (about 91 mi/h). How much work is done on a rider and his sled (assuming a total mass of 85.6-kg) by nonconservative forces?
J
Explanation / Answer
part a )
dKE = dU
1/2 * mvf^2 - 1/2*mvi^2 = mgho - mghi
vf^2 - vi^2 = 2g(hi - hf)
vi = 0
hf - hi = 122 m
vf = sqrt(2g(hi -hf)
vf = 48.8999 = 48.9 m/s
part b )
Wnc = 1/2 * m (vf^2-vi^2) + mg(hf-hi)
hf - hi = -122 m
m = 85.6 kg
vf = 35.8 m/s
Wnc = -47489.168 J