Question

In an isolated system, two cars, each with a mass of 1,000 kg, collide. Car 1 is

initially at rest, while Car 2 was moving at 10 m/s. They move off together.
What is their speed?
A. O m/s
B. 20 m/s
c. 5 m/s
D. 10 m/s

Answer 1

Their speed is 5 m/s.

c. 5 m/s

Step-by-step explanation:

The situation described in the given problem is an example of inelastic collision where the objects stick together and the kinetic energy won’t be conserved. Some of the kinetic energy might transform to thermal energy or some other form of energy.

Here the mass of first vehicle
`M_1=1000 kg`

mass of second vehicle
`M_2=1000 kg`

velocity of the first vehicle
`v_1=10m/s`

velocity of the second vehicle
`v2=0m/s`

Since the masses of the vehicles are combined after the collision their velocities also will be combines.

Therefore mass of the system after collision =
`M_1+M_2`

velocity of the system after collision = v

According to the law of conservation of momentum
`M_1 v_1+M_2 v_2=(M_1+M_2)v`

`1000 * 10+1000 * 0=(1000+1000) * v`

`10000=2000 * v`

`v=10000/2000=5m/s`