Question

A 2.0-kilogram ball traveling north at 4.0 meters per second collides head on with a 1.0 kilogram ball traveling south at 8.0 meters per second. What is the magnitude of the total momentum of the two balls after the collision? *

Answer 1

A: 0.0 kg•m/s

Step-by-step explanation:

Answer 2

0 (zero)

Step-by-step explanation:

Assuming the collision is elastic, the total momentum is conserved, so the total momentum of the two balls after the collision will be equal to the total momentum before the collision.

Therefore, we just need to calculate the total momentum before the collision. Assuming north as positive direction, we have:

- Momentum of ball 1 :
`p_1 = mv=(2.0 kg)(+4.0 m/s)=+8.0 kg m/s`

- Momentum of ball 2:
`p_2 = mv=(1.0 kg)(-8.0 m/s)=-8.0 kg m/s`

So, the total momentum is

`p=p_1+ p_2 = +8.0 kg m/s+(-8.0 kg m/s)=0`

so, the total momentum after the collision will also be zero.