Problem 10.64 the maximum energy a bone can absorb without breaking is surprisingly small. for a healthy human of mass 67 kg , experimental data show that the leg bones can absorb about 200 j . part a from what maximum height could a person jump and land rigidly upright on both feet without breaking his legs? assume that all the energy is absorbed in the leg bones in a rigid landing. neglect any friction.

h = 0.30 m

Explanation:

A person jumping from height h would possess potential energy = m g h

which will convert completely into kinetic energy as person hits the ground. Now, the maximum energy absorbed by the person can be = 200 J

m = 67 kg

g = 9.8 m/s²

⇒ m g h = 200 J

⇒ h = 200 J / (67 kg × 9.8 m/s²) = 0.30 m

Hence, a person can land safely on both legs without breaking them from a height of 0.30 m only.

the design of a ski jumping suit involves a trade-off between giving the skiers lift to get higher jumps and ensuring the skier does not face a lot of drag before the jump itself. an expansive suit may to lift the skier higher, but at the same time, it will also increase the air resistance. higher air resistance as the skier goes down the slope limits the speed of the jump. a big suit also increases the risk of losing balance or control, especially if there's a strong gust of wind. while technologically enhanced suits a lot, clothing is not the only factor in a ski jumper’s success. gathering speed while skiing down the slope, ensuring good speed on the ramp, and maintaining good body posture and form in the air all contribute to a ski jumper's success.