Question

A toy train of m=0.60 kg moves at 20m/s along a straight track. It bumps into another train of M=1.5kg moving in the same direction. They stick together and continue on the track at a speed 12 m/s. What was the speed in m/s of the second train just before the collision?

Answer 1

Answer:8.8 m/s

Step-by-step explanation:

Given

mass of train
`m_1=0.6 kg`

velocity of Train
`v_1=20 m/s`

mass of another train
`m_2=1.5 kg`

Final velocity of both train
`v=12 m/s`

Let
`v_2` be the velocity of
`m_2` before collision

As external Force is zero therefore change in momentum is zero

conserving Momentum

`m_1v_1+m_2v_2=(m_1+m_2)v`

`0.6* 20+1.5* v_2=(0.6+1.5)\cdot 12`

`1.5* v_2=25.2-12`

`v=(13.2)/(1.5)=8.8 m/s`