Question

An empty train car of mass 2.0 x 10^4 kg coasts along at 10 m/s. A 3000-kg boulder is suddenly dropped vertically into the car. Find the speed of the car immediately after the boulder is dropped.

Answer 1

Answer:8.69 m/s

Step-by-step explanation:

Given

mass of Empty train
`m=2* 10^4 kg`

velocity of car
`v=10 m/s`

mass of Boulder
`M=3000 kg`

Since no External force is acting therefore conserving Momentum

Train and boulder moves with same velocity after collision

`m v=(M+m)v'`

`2* 10^4* 10=(2* 10^4+3000)v'`

`v'=(20,000* 10)/(23000)`

`v'=8.69 m/s`