Question

A 5000-kg freight car collides with a 10,000-kg freight car at rest. They couple upon collision and move at 2 m/s. What was the initial speed of the 5000-kg car? 4 m/s 5 m/s 6 m/s 8 m/s none of these.

Answer 1

The initial speed of the 5000-kg car is 6 m/s.

To calculate the initial speed of the car, we apply the law of conservation of momentum

Law of conservation of momentum

The Law of conservation of momentum states that for two colliding bodies, the total momentum of the system before the collision is equal to the total momentum after collision provided there is no net external force acting on the system.

Formula:

• mu+m'u' = V(m+m')............... Equation 1

Where:

• m = mass of the first car
• m' = mass of the second car
• u = initial speed of the first car
• u' = initial speed of the second car
• V = common speed.

From the question,

Given:

• m = 5000 kg
• m' = 10000 kg
• u' = 0 m/s (at rest)
• V = 2 m/s

Substitute these values into equation 1

• 5000(u)+10000(0) = 2(5000+10000)
• 5000u+0 = 30000
• u = 30000/5000
• u = 6 m/s.

Hence, The initial speed of the 5000-kg car is 6 m/s.

Learn more about the law of conservation of momentum here: https://brainly.com/question/7538238