Question

a stone is thrown horizontally at a speed of 5.o m/s from the top of a cliff 78.4 m high. How long does it take the stone to reach the bottom of the cliff?

Answer 1

distance = 1/2*g*t^2. You know distance and g, solve for time. It doesn't matter what the horizontal speed is as the stone will fall at the same rate as if it were dropped. True, the stone won't land at the foot of the cliff but further away from the cliff.