A $4.00 \mathrm{~kg}$ ball is moving at $2.00 \mathrm{~m} / \mathrm{s}$ to the WEST and a $6.00 \mathrm{~kg}$ ball is moving at $2.00 \mathrm{~m} / \mathrm{s}$ to the NORTH. The total momentum of the system is
A) $21.6 \mathrm{~kg} \mathrm{~m} / \mathrm{s}$ at an angle of 17.7 degrees NORTH of WEST.
B) $21.6 \mathrm{~kg} \mathrm{~m} / \mathrm{s}$ at an angle of 56.3 degrees NORTH of WEST.
C) $21.6 \mathrm{~kg} \mathrm{~m} / \mathrm{s}$ at an angle of 45.2 degrees SOUTH of WEST.
D) $14.4 \mathrm{~kg} \mathrm{~m} / \mathrm{s}$ at an angle of 45.2 degrees SOUTH of WEST.
E) $14.4 \mathrm{~kg} \mathrm{~m} / \mathrm{s}$ at an angle of 56.3 degrees NORTH of WEST.

Question

Quizplus · Accepted Answer

The total momentum is calculated using vector addition. The momentum of the 4.00 kg ball is $8.00 \, \text{kg m/s}$ to the WEST, and the momentum of the 6.00 kg ball is $12.00 \, \text{kg m/s}$ to the NORTH. The resultant momentum magnitude is $\sqrt{8^2 + 12^2} = 14.4 \, \text{kg m/s}$, and the angle is $\tan^{-1}(12/8) = 56.3$ degrees NORTH of WEST.

A 4.00 kg4.00 \mathrm{~kg}4.00 kg Ball Is Moving At 2.00 m/s2.00 \mathrm{~m} / \mathrm{s}2.00 m/s To the WEST and A

A $4.00 \mathrm{~kg}$ Ball Is Moving At $2.00 \mathrm{~m} / \mathrm{s}$ To the WEST and A