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Unformatted text preview: Create assignment, 00223, Homework 6, Oct 03 at 7:14 pm 1 This printout should have 8 questions. Multiplechoice questions may continue on the next column or page find all choices before answering. The due time is Central time. Stopped By a Utility Pole 09:02, trigonometry, numeric, > 1 min, nor mal. 001 A(n) 1500 kg car moving with a speed of 15 m / s collides with a utility pole and is brought to rest in 0 . 3 s. Find the magnitude of the average force exerted on the car during the collision. Correct answer: 75000 N. Explanation: The impulse equals the change in momen tum, therefore F t = p = mv f mv i . Thus F = mv f mv i t = (1500 kg)(15 m / s) (0 . 3 s) = 75000 N k ~ F k = 75000 N , where the negative sign indicates the direction of the force is opposite to that of the cars original motion. Billiard Collision 04 09:04, trigonometry, numeric, > 1 min, nor mal. 002 Assume an elastic collision (ignoring friction and rotational motion). A queue ball initially moving at 8 m / s strikes a stationary eight ball of the same size and mass. After the collision, the queue balls final speed is 4 . 6 m / s . 8 m / s 4 . 6 m / s Before After Find the eight balls angle with respect to the original line of motion of the queue ball. Correct answer: 35 . 0996 . Explanation: Let : v q i = 8 m / s and v q f = 4 . 6 m / s . Given m q = m e = m , ~p e i = 0, ~p m~v , and ~p ~p p 2 . Conservation of energy (and multiplying by 2 m ) gives p 2 q f + p 2 e f = p 2 q i . (1) Conservation of momentum (specifically, ~p q f + ~p e f = ~p q i , and squaring) gives ( ~p q f + ~p e f ) ( ~p q f + ~p e f ) = ~p q i ~p q i ....
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 Spring '11
 Chiu
 Physics, Work

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