A brave stunt devil would like to recreate one of Evil Kniev…
A brave stunt devil would like to recreate one of Evil Knievel’s famous jumps, launching himself and his bike across line of trucks which are arranged side by side, each of which is roughly 2.6 m wide. Strangely, he decides to do this by using a very stiff springboard, which is originally compressed by 1.5 m, to push the bike up a ramp which is inclined at an angle of 23° and is 3.0 m long from the edge of the springboard (see figure). Ignoring the effects of air resistance, suppose the stunt devil would like to jump 25 trucks, needing to reach a speed of about 30 m/s by the edge of the ramp. a) If the stunt devil and the bike have a combined mass of 160 kg, what must the spring constant of the springboard be in order for the stunt devil to make the jump if the ramp is effectively frictionless? b) What total work must be done on the stunt devil for him to make the jump? Which forces do work as he moves along the ramp? c) Suppose the ramp does provide a small frictional force on the tires of the bike, doing -3,000 J of work on the stunt devil as he reaches the edge of the ramp. By how much further should the spring be compressed for the stunt devil to safely make the jump? d) If the springboard of part c) is in contact with the stunt devil for about 1.8 s, what average Power does the spring deliver to the stunt devil?
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