Question

A boy of mass 49.6 kg is initially on a skateboard of mass 2.00 kg, moving at a speed of 10.4 m/s. The boy falls off the skateboard, and his center of mass moves forward at a speed of 10.9 m/s. Find the final velocity of the skateboard.

Answer 1

Answer:2 m/s opposite to initial direction

Step-by-step explanation:

Given

mass of boy
`m=49.6 kg`

mass of skateboard
`m_2=2 kg`

speed of skateboard
`u=10.4 m/s`

speed of com of boy
`v_0=10.9 m/s`

Let v be the speed of skateboard after fall

conserving momentum

`(m+m_2)u=m* v_0+m_2* v`

`(49.6+2)\cdot 10.4=49.6* 10.9+2* v`

`536.64=540.64+2v`

`2v=536.64-540.64`

`2v=-4`

`v=-2 m/s`

v=2 m/s opposite to original direction