Question

A student throws a 4 kg rock against a wall. The kinetic energy of the rock was 50 J. What is the speed of the rock as it hit the wall?​

Answer 1

The velocity with which the ball hit the wall is 5 m/s

Explanation:

Given as :

The mass of rock = 4 kg

The kinetic energy of the rock = 50 J = 50 kg
`[m^(-1)s]^(2)`

Let The speed of rock = V

So, From Kinetic energy formula

Kinetic energy ( K E ) =
`(1)/(2)* mass* velocity^(2)`

Or, 50 J =
`(1)/(2)* 4* v^(2)`

Or,
`(50* 2)/(4)` = V²

Or, 25 = V²

∴ V =
`√(25)` = 5 m/s

Hence The velocity with which the ball hit the wall is 5 m/s Answer