1) A bungee jumper: A bungee jumper wishes to jump from

1) A bungee jumper: A bungee jumper wishes to jump from a bridge 100m above the river. The bungee cord is a length of rubber (assumed massless) that stretches 20% when the jumper hangs from it. The jumper requires the cord to stop their fall exactly at the river level. Find (a) what length of bungee cord is required. (b) what height above the river the jumper will end up at after vertical oscillations have stopped. (c) the period of small amplitude vertical oscillations. 2) A back-of-the-envelope plasmon resonance Consider a cube with an electron density n that is balanced by stationary positive charge to make the volume neutral. The cube has sides of length d. Now imagine that the electrons are displaced by a distance ? (