Question

A 1000 kg train car traveling at 12 m/s on a level track has 400 kg of sand dumped, vertically, into it. What is the final speed of the train car after the sand is dumped into it? Ignore friction

Answer 1

Answer:

The final speed of the train car is 8.57 m/s.

Explanation:

Given that,

Mass of train car = 1000 kg

Mass of sand = 400 kg

Speed of train car = 12 m/s

We need to calculate the final speed of the train car after the sand is dumped

Using conservation of momentum

$m_{1}u_{1}=(m_{1}+m_{2})v$...(I)

Put the value in the equation (I)

$1000\times12=(1000+400)v$

$v=\dfrac{1000\times12}{1400}$

$v=8.57\ m/s$

Hence, The final speed of the train car is 8.57 m/s.