OCR MEI
Further Mechanics Major
2021
November
Q5
6 marks
Standard +0.8
5 Two small uniform smooth spheres A and B , of equal radius, have masses 2 kg and 4 kg respectively. They are moving on a horizontal surface when they collide. Immediately before the collision, A has speed \(6 \mathrm {~m} \mathrm {~s} ^ { - 1 }\) and is moving along the line of centres, and B has speed \(2.5 \mathrm {~m} \mathrm {~s} ^ { - 1 }\) and is moving along a line which is perpendicular to the line of centres (see diagram).
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The direction of motion of B after the collision makes an angle of \(45 ^ { \circ }\) with the line of centres.
Determine the coefficient of restitution between A and B .