Question

MEDAL GIVEN TO CORRECT ANSWER.
Two rams run toward each other. One ram has a mass of 50 kg and runs west with a speed of 8 m/s, while the other has a mass of 40 kg and runs east with a speed of 5 m/s. What is the total momentum of the system made up of the two rams?

A. 600 kgm/s east
B. 200 kgm/s west
C. 600 kgm/s west
D. 200 kgm/s east

Answer 1

200 to the west bc ram is 400 to the west and ram b is 200 to the east

Answer 2

The correct answer is B.

Answer 3

Step 1: find the momentum for each ram.

Momentum is mass times velocity so,

50 x 8 = 400

40 x 5 = 200

Answer 4

Step 2: find the total momentum by subtracting

400 - 200 = 200 Kgm/s

Answer 5

WARNING: we SUBTRACTED because the rams were traveling in OPPOSITE directions. If, however, they had been traveling in the SAME direction, we would have ADDED!

Answer 6

Step 3: find the DIRECTION of the total momentum

The final direction will be that of the LARGEST momentum. The largest momentum was that of the 50kg ram, so the direction of the total momentum will be WEST.

Answer 7

So the correct answer is B. 200 kgm/s west