PHYSICS
posted by Rachel .
At the Earth's surface, a projectile is launched straight up at a speed of 8.4 km/s. To what height will it rise? Ignore air resistance and the rotation of the Earth.

Set the initial kinetic energy equal to the potential energy change at the highest elevation, and solve for that elevation.
(1/2)mV^2 = GMm/R  GMm/(R + h)
Solve for the height h. m cancels out
M is the mass of the earth, G is the universal gravity constant and R is the earth's radius. 
answer is kys