A toy car of mass 2.0 kg moving to the right with a speed of 8.0 m/s collides perfectly inelastically with another toy car of mass 3.0 kg that is moving to the left with a speed of 2.0 m/s.Immediately after the collision the velocity of the system is
A)4.4 m/s to the right.
B)2.0 m/s to the right.
C)0 m/s
D)-2.0 m/s to the right.
E)10 m/s to the right.

Question

Quizplus · Accepted Answer

In a perfectly inelastic collision, the two objects stick together after the collision. The total momentum before the collision equals the total momentum after the collision. The initial momentum is $ (2.0\, \text{kg} \times 8.0\, \text{m/s}) + (3.0\, \text{kg} \times -2.0\, \text{m/s}) = 16.0\, \text{kg}\cdot\text{m/s} - 6.0\, \text{kg}\cdot\text{m/s} = 10.0\, \text{kg}\cdot\text{m/s} $. The total mass after the collision is $2.0\, \text{kg} + 3.0\, \text{kg} = 5.0\, \text{kg}$. Therefore, the velocity of the system after the collision is $ \frac{10.0\, \text{kg}\cdot\text{m/s}}{5.0\, \text{kg}} = 2.0\, \text{m/s} $ to the right.

A Toy Car of Mass 2