Question

A girl throws a rock horizontally, with a velocity of 10 m/s, from a bridge. It falls 20 m to the water below. How far does the rock travel horizontally before striking the water?

Answer 1

20 m

Step-by-step explanation:

The initial vertical velocity is 0. We can find the time (t) that it takes to fall 20 m (h) using the following expression.

h = 1/2 × g × t²

where,

g is the acceleration due to the gravity

t = √(2h/g) = √(2 × 20 m/ 9.8 m/s²) = 2.0 s

The rock is in the air during 2.0 s and moves horizontally at a constant speed of 10 m/s. The horizontal distance traveled is:

d = v × t = 10 m/s × 2.0 s = 20 m