A ball is thrown horizontally from a cliff at a speed of 15 m/s and strikes the ground 45 meters from the base of the cliff. How high was the cliff?
Assuming air resistance is negligible, we can state that the ball flew for 3 seconds (
This then allows us to use a kinematic equation (SUVAT equation) to solve for the vertical distance travelled. Initial (vertical) velocity, called ‘u’ below is zero as the ball is thrown horizontally.
I’d quote this to 2 sig. figs., as the data in the question implies.