El. A ball is thrown onto a rough floor at an angle 8. If it rebounds at an angle and the coefficient of kinetic friction is u, determine: (a) the coefficient of restitution e. (b) Further simplify the expression if 0 = = 45°. (c) From the previous part, determine the coefficient of friction u if e = 0.6. Neglect the size of the ball. Hint: Show that during impact, the average impulses in the x and y directions are related by Ix = μly. Since the time of impact is the same, FAt = μF, At or F₂ = µFy. E2. The four smooth balls each have the same mass m. If A and B are rolling forward with velocity v and strike C, explain why after collision C and D each move off with velocity v. Why doesn't D move off with velocity 2v? The collision is elastic, e = 1. Neglect the size of each ball. 10 td AB C D x

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