Question

14. A 5,000 kg train is traveling at a velocity of 100 m/s and hits another train. The two trains stick together, and the new velocity is 50 m/s. What is the mass of the second
train?

A. 15.000 kg
B. 8.000 kg
C. 5,000 kg
D. 10.000 kg

Please help ASAP

Answer 1

Answer:

C

Explanation:

• Momentum of first train is = m * v

                                                    = (5000 kg)·(100 m/s)

                                                    = 500,000 kg·m/s.

• Momentum after collision is = (5000+M) kg)·(50 m/s)

• And using conservation of momentum

                          5000+M) kg)·(50 m/s) = 500,000 kg·m/s

         Dividing by 50 m/s and subtracting 5000 kg, we have ...

                                          (5000 +M) kg = 10,000 kg

                                                        M kg = 5000 kg