A projectile is fired from a point at height h above horizontal ground with speed u in an arbitrary direction. It eventually strikes the ground with speed v. Which relation is always correct, independent of the angle of projection?
Options

Question

A projectile is fired from a point at height h above horizontal ground with speed u in an arbitrary direction. It eventually strikes the ground with speed v. Which relation is always correct, independent of the angle of projection?

Options

G1 Physics · Accepted Answer

Only gravity does work. Using conservation of mechanical energy between launch and impact, ½ μ \mu μ ² + mgh = ½mv². Therefore, v² = u² + 2gh. Thus the impact speed depends on u and h, but not on the angle of projection.