A 5 m by 9 m raft whose mass is 18000 kg

floats in fresh water. A 8590 kg load is
dropped on the raft. The acceleration of gravity is 9.8 m/s2. With what frequency does the raft bob up and down?

Answer in units of Hz.

1. find buoyancy force, find depth

2. use Hooke's law, to find force constant
3. find frequency by using the formula for spring-mass system SHM