Question

A 1200 kg car traveling north at 10 m/s is rear-ended by a 2000 kg truck traveling at 30 m/s. What is the total momentum before and after the collision?

Answer 1

Answer:

The total momentum before and after collision is 72000 kg-m/s.

Explanation:

Given that,

Mass of car = 1200 kg

Velocity of car = 10 m/s

Mass of truck = 2000 kg

Velocity of truck = 30 m/s

Using conservation of momentum

The total momentum before the collision is equal to the total momentum after collision.

$m_{1}v_{1}+m_{2}v_{2}=(m_{1}+m_{2})V$

Where, $m_{1}$=mass of car

$v_{1}$ =velocity of car

$m_{1}$=mass of truck

$v_{1}$ =velocity of truck

Put the value into the formula

$1200\times10+2000\times30=(1200+2000)V$

$V=\dfrac{1200\times10+2000\times30}{(1200+2000)}$

$V = 22.5\ m/s$

Now, The total momentum before collision is

$P=m_{1}v_{1}+m_{2}v_{2}$

$P=1200\times10+2000\times30$

$P=72000\ kg-m/s$

The total momentum after collision is

$P=(m_{1}+m_{2})v_{2}$

$P=(1200+2000)\times22.5$

$P= 72000 kg-m/s$

Hence, The total momentum before and after collision is 72000 kg-m/s.