A Level Physics Question on Gravitational

LastRide7 SG

Certain tektites found on Earth have a composition identical with that of lunar granite. It is thought that they may be debris from a volcanic eruption on the Moon. The gravitational potential between the surface of the Moon and the surface of the Earth varies along the line of centres. At Point P, the gravitational potential is a maximum. Please refer to the link for the figure.
http://i71.photobucket.com/albums/i159/J…

(a) If a tektite is to reach the Earth, it must be projected from the volcano on the Moon with a certain minimum speed v. Making appropriate values from the graph, find this speed.

(b) Discuss very briefly if a tektite will reach the Earth's surface with a speed less than, equal to or greater than the speed of projection. (neglect atmospheric resistance)

(c) Calculate the speed of the tektite just before it hits the Earth.

Shootme SG

a) take the difference in potential energy between moon and point p = 1/2m(v^2)

then find v.

b) we deduce from the formula in a) difference in PE is directly proportional to V, thus greater diff. in PE bet. earth and point p-> greater speed

c) same formula as a)

I am in Ns for almost 2 years, you may wish to double check my answer as I can't even pass O level standard now....NS makes us dumb