A mass of 60 kg is held 1.80 x10^7 metres above the surface of a planet that has a radius of 3.75 x10^7 metres and a mass of 4.50 x10^28 kg.?

A mass of 60 kg is held 1.80 x10^7 metres above the surface of a planet that has a radius of 3.75 x10^7 metres and a mass of 4.50 x10^28 kg.

a) If the mass were to be dropped freely to hit the surface of the planet, with what velocity would it collide with the planet? _____m/s       

b) How much work would be required to lift it 7.00 x10^6 m from its original point 1.80x 10^7 m above the ground? _____J

c) What would the escape velocity be from the surface of the planet to reach deep space? _____m/s

d) If a giant spring with k=1.90 x10^9 N/m were compressed by 20 m and the mass were shot straight up into space:

i) Ignoring the effect of the change in gravitational potential energy, what would the velocity of the mass be as it left the spring?______

ii) How high would the mass be flung?______