Question

1. What is the range of the projectile launched horizontally at 25 m/s from the 18 m-high cliff edge as shown in the diagram? 

2. A ball rolls off a horizontal roof at 15 m/s. How far will the ball have fallen vertically when it reaches a speed of 24 m/s?

Answer 1

1 The range is

$$R=vt=v\sqrt{2h/g}=48\text{ m}.$$

2 The height is

$$h=\frac{v_y^2}{2g}=\frac{24^2}{2·9.8}=29\text{ m}.$$