We have a hole that leads straight through the center of the Earth. We neglect air resistance and assume that the Earth has uniform density ρ. How long would it take to fall through the center of the Earth and reach the other side of the planet?
A mass m is attached to a spring S and oscillates with a period T.
(a) What would be the period of the oscillations on a planet with surface gravity 3g?
(b) What would be the period of the oscillation if two springs S are connected in series or in parallel?