Question

A stone is dropped from rest from the top of a cliff into a pond below. If its initial height is 10 m, what is its speed when it hits the water?

Answer 1

14 m/s

Step-by-step explanation:

The motion of the stone is a free fall motion, so an accelerated motion with constant acceleration g = 9.8 m/s^2 towards the ground. So, we can use the following SUVAT equation:

`v^2 -u^2 = 2gh`

where

v is the final speed of the stone as it reaches the water

u = 0 is the initial speed

g = 9.8 m/s^2 is the acceleration

h = 10 m is the distance covered by the stone

Solving for v, we find

`v=√(u^2+2gh)=√(0+2(9.8 m/s^2)(10 m))=14 m/s`