Two carts moving in the same direction, as shown in the figure below, collide.Cars What is the velocity of the two carts AFTER the collision, assuming that they stick together after the collision.

Question

Two carts moving in the same direction, as shown in the figure below, collide.

What is the velocity of the two carts AFTER the collision, assuming that they stick together after the collision.

i don't know how to upload a pic but

one cart is 2kg ---> and the other is 4kg--->

and they move at 6m/s

Answer 1

Conservation of momentum (mv)

Momentum before collision = 6 x 2 + 6 x 4 = 36 kg m/s

Momentum after collision = 6 v = 36 , giving v = 6 m/s

Incidentally how do they collide if they are going at the same speed in the same direction initially ??