A 1050 kg car moving south at 10.0 m/s collides with a 2650 kg car moving north. The cars stick together and move as a unit after the collision at a velocity of 5.16 m/s to the north. Find the velocity of the 2650 kg car before the collision

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A 1050 kg car moving south at 10.0 m/s collides with a 2650 kg car moving north.
The cars stick together and move as a unit after the collision at a velocity of 5.16 m/s to the north.
Find the velocity of the 2650 kg car before the collision
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This is a conservation of momentum problem where
momentum = mass*velocity (MV)

The north-bound car will have more momentum than
The south-bound car.

Given:

1,050*10.0 = 10,500 kg m/s (going south)
2,650*V = momentum of car going north
(1050+2650)*(-5.16) = combined momentum going north

HENCE:

10500 –2650*V = (1050+2650)*-5.16

-2560V = -19092-10500

-2560V = -29592

V = -29592/-2560

V = 11.56 m/s