9. 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. 10,000 kg d. 5,000 kg

D. 5000 kg

Step-by-step explanation:

We assume the second train was standing still and that momentum is conserved. The the product of mass and velocity before the collision is

(5000 kg)·(100 m/s) = 500,000 kg·m/s.

After the collision, where M is the mass of the second train, the momentum is ...

((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

The mass of the second train is 5000 kg.

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step-by-step explanation:

answer: the proof is mentioned below.

step-by-step explanation:

since, given:   lines bc = ef

prove:   lines ac > ef

          statements                                           reason

1. bc=ef                                           1. given

2. ac= ab+bc                                 2. because b is the point between the  

                                                            line segment ac

3.   ac > bc                                       3. because if a line segment is equal to

                                                          the sum of two line segments then it is

                                                          always greater then each of these

                                                          individual line segments

4. ac > ef                                         4. by equality property.