8 In this question use \(g = 9.8 \mathrm {~m} \mathrm {~s} ^ { - 2 }\)
Omar, a bungee jumper of mass 70 kg , has his ankles attached to one end of an elastic cord.
The other end of the cord is attached to a bridge which is 80 metres above the surface of a river.
Omar steps off the bridge at the point where the cord is attached and falls vertically downwards.
The cord can be modelled as a light elastic string of natural length \(L\) metres and modulus of elasticity 2800 N
Model Omar as a particle.
8
- Given that Omar just reaches the surface of the river before being pulled back up, find the value of \(L\)
Fully justify your answer.
8 - If Omar is not modelled as a particle, explain the effect of revising this assumption on your answer to part (a).