Question

5. Mark drops a 4.0 kg book from a height of 5.0 m. How fast is the book moving when it hits the ground?

Answer 1

9.9 m/s

Step-by-step explanation:

All of the PE (mgh) will be cnverted to KE ( 1/2 m v^2)

mgh = 1/2 m v^2

gh = 1/2 v^2

v = sqrt (2 gh) Note that the mass of the book is not needed !

v = sqrt ( 2 * 9.81 m/s^2 * 5) = 9.9 m/s