posted by keitanako .
A meteorite of mass 1*10^4kg is approaching head-on a planet of mass 5*10^29kg and radius 5*10^4km. Assume that the meteorite is initially at a very large distance from the planet where it has a speed 3*10^2km/s. Take 6.67*10^-11.
Determine the speed of the meteorite (in m/s) just before it hits the surface of the planet. (The planet has no atmosphere, so we can neglect all friction before impact)
please tell the formuka
I know its the initial KE+initial PE=final KE... but how do we calculate the initial PE? GMm/R.... but what R do we sue ehre? Its beens tated that the meteorite is already really far away from the planet initially..???
Given that its really far away from the planet you can assume that PE = 0