at the earths surface, a projectile is launched straight up at a speed of 10km/. To what height will it rise?

i need some major help here please don't know where to begin on this one!

1 answer

Do you mean 10 km/s?

Solve the energy equation
(1/2) m V^2 - G mM/Re = -GmM/(Re + h)

Re is the earth's radius and h is the maximum altitude. V is the initial velocity. The -GmM tems are the poential energy in the inverse-square gravitaional field of the Earth. M is the Earth's mass.

Ig you don't want to have to look up G, remember that
GM/Re^2 = g, the acceleration of gravity at the Earth's surface.

The first equation can be rewritten, after cancelling out m's,
(1/2) V^2 = g Re [1 - 1/(1 + h/Re)]

Solve for h, but check my math first