A 0.650 \mathrm{~kg} ball moving at 5.00 \mathrm{~m} / \mathrm{s} collides with a 0.750 \mathrm{~kg} ball that is originally at rest. After the collision, the 0.750 \mathrm{~kg} ball moves off with a speed of 4.00 \mathrm{~m} / \mathrm{s}, and the 0.650 \mathrm{~kg} ball moves off at a right angle to the final direction of motion of the 0.750 \mathrm{~kg} ball.
What is the final speed of the 0.650 \mathrm{~kg} ball?
Answer Choices
A. 1.92 \mathrm{~m} / \mathrm{s}
B. 2.32 \mathrm{~m} / \mathrm{s}
C. 3.00 \mathrm{~m} / \mathrm{s}
D. 4.64 \mathrm{~m} / \mathrm{s}
E. 5.77 \mathrm{~m} / \mathrm{s}