Question

A 4.00-kg object traveling 20.0 m/s west collides with a 6.00-kg mass object traveling 12.0 m/s east. The collision is perfectly elastic, what is the velocity of the 4.00-kg object after the collision?

Answer 1

Answer:

The velocity of the 4.00 kg object after the collision is 12 m/s.

Explanation:

Given that,

Mass of object $m_{1} = 4.00\ kg$

Velocity of object $v_{1} = 20.0\ m/s$

Mass of another object $m_{2} = 6\ kg$

Velocity of another object $v_{2}= 12.0\ m/s$

We need to calculate the relative velocity

$v_{r}=v_{1}-v_{2}$

$v_{r}=20-12=8\ m/s$

The relative velocity is 8 m/s in west before collision.

We know that,

In one dimensional elastic collision, the relative velocity before collision equals after collision but with opposite sign.

So, The relative velocity after collision must be 8 m/s in east.

So, The object of 6.00 kg is going 20 m/s and the object of 4.00 kg is slows down to 12 m/s.

Hence, The velocity of the 4.00 kg object after the collision is 12 m/s.