Question

A stunt performer falls off a wall that is 3.1 m high and then lands on a mat.What is his impact velocity?A. 5.1 m/sB. 6.5 m/sC. 3.4 m/sD. 7.8 m/s

Answer 1

Given data

*The given height is h = 3.1 m

*The value of the acceleration due to gravity is g = 9.8 m/s^2

The formula for the impact velocity is given by using the conservation of energy as

`\begin{gathered} (1)/(2)mv^2=mgh \\ v=\sqrt[]{2gh} \end{gathered}`

Substitute the known values in the above expression as

`\begin{gathered} v=\sqrt[]{2*9.8*3.1} \\ =7.79\text{ m} \\ \approx7.8\text{ m} \end{gathered}`

Hence, the impact velocity is v = 7.8 m/s and the correct option is (D)