Question

Two trains approach one another. Train A has a mass of 500,00 kg and is moving at 34.0 m/s. Train B has a mass of 350,00 kg and is moving at 42 m/s. They collide and stick together. What is the velocity and direction of the combined masses

Answer 1

A has a mass of 500,00 (I assume you mean 500,000)

A moves east, positive direction
B moved west, negative

Initial momentum east
= 500, 000 *34 - 350,000 * 42

= 170*10^5 - 147*10^5 = 23*10^5

that will be the final too
final mass = 5+3.5 = 8.5*10^5
so
8.5*10^5 V = 23*10^5

V = + 2.71 east

Answer 2

what about a 5,000 kg truck rear-ends a 1200 kg car that has been traveling at 13 m/s, causing the truck to slow down and the car to speed up. What is the final velocity?

Answer 3

Final velocity of the car that is

Answer 4

I do not know.
Questions:
initial velocity of truck?
do they stick together?

Answer 5

angie, post your own questions, hanging on the tail of other questions wont work.

wondering which one has been traveling at 13m/s? One can't assume conservation of energy here.

Answer 6

reposted- sorry for the confusion and thanks of the help