Question

A 1530 kg car moving south at 12.1 m/s collides with a 2560 kg car moving north. The cars stick together and move as a unit after the collision at a velocity of 5.48 m/s to the north. Find the velocity of the 2560 kg car before the collision. Assume that North is positive. Answer in units of m/s.

Answer 1

Answer:

16 m/s north

Explanation:

According to the law of momentum conservation, total momentum before and after must be the same

Total momentum after the collision as both cars stick together as 1 unit traveling at speed of 5.48m/s to the north

(m + M)V = (1530 + 2560)*5.48 = 22413 kgm/s

So the total momentum before must also be 22413, which is made of

$mv_1 + Mv_2 = 22413$

$1530*(-12.1) + 2560v_2 = 22413$

$2560v_2 = 22413 + 18513 = 40926$

$v_2 = 40926 / 2560 \approx 16 m/s$ north