Question

a train car moving to the right at 10 m/s collides with a parked train car.they stick together and roll along the track. if the moving car has a mass of 8,000 kg and the parked car has gas of 2,000 kg, what is their combined velocity after the collision

Answer 1

To solve this problem, we can use the law of conservation of momentum, which states that the total momentum of a closed system remains constant. Before the collision, the momentum of the moving car is:

p1 = m1v1

where m1 is the mass of the moving car and v1 is its velocity. Similarly, the momentum of the parked car is:

p2 = m2v2

where m2 is the mass of the parked car and v2 is its velocity, which is zero since it is parked. After the collision, the two cars stick together and move with a combined velocity v. The total momentum of the system is:

p = (m1 + m2)v

According to the law of conservation of momentum, the total momentum before and after the collision must be equal. Therefore, we can write:

p1 + p2 = p

m1v1 + m2(0) = (m1 + m2)v

Simplifying this equation, we get:

v = (m1v1) / (m1 + m2)

Substituting the given values, we get:

v = (8,000 kg x 10 m/s) / (8,000 kg + 2,000 kg)

v = 8 m/s

Therefore, the combined velocity of the two cars after the collision is 8 m/s to the right.