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Unformatted text preview: Patel (sap785) homework #7 shubeita (58645) 1 This print-out should have 12 questions. Multiple-choice questions may continue on the next column or page find all choices before answering. 001 10.0 points A student performs a ballistic pendulum experiment using an apparatus similar to that shown in the figure. Initially the bullet is fired at the block while the block is at rest (at its lowest swing point). After the bullet hits the block, the block rises to its highest position, see dashed block in the figure, and continues swinging back and forth. The following data is obtained: the maximum height the pendulum rises is 5 cm, at the maximum height the pendulum sub- tends an angle of 48 . 2 , the mass of the bullet is 62 g, and the mass of the pendulum bob is 841 g. The acceleration of gravity is 9 . 8 m / s 2 . 841 g 62 g v i v f 4 8 . 2 5 cm Determine the initial speed of the projec- tile. Correct answer: 14 . 4181 m / s. Explanation: Let : = 48 . 1897 , m 1 = 62 g , m 2 = 841 g , and h = 5 cm = 0 . 05 m . The final velocity is v f = radicalbig 2 g h. Using conservation of momentum m 1 v i = ( m 1 + m 2 ) v f , so v i = bracketleftbigg ( m 1 ) + ( m 2 ) m 1 bracketrightbigg v f = bracketleftbigg ( m 1 ) + ( m 2 ) m 1 bracketrightbigg radicalbig 2 g h = bracketleftbigg (62 g) + (841 g) (62 g) bracketrightbigg radicalBig 2 (9 . 8 m / s 2 ) (0 . 05 m) = 14 . 4181 m / s . 002 10.0 points You are given two carts, A and B. They look identical, and you are told that they are made of the same material. You place A at rest on an air track and give B a constant velocity di- rected to the right so that it collides elastically with A. After the collision, both carts move to the right, the velocity of B being smaller than what it was before the collision. What do you conclude? 1. The two carts are identical 2. need more information 3. Cart B is hollow 4. Cart A is hollow correct Explanation: Because B continues to move in the original direction of motion albeit at a slower speed, its inertial mass must be larger than that of A. Since they are made of the same materialA....
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- Spring '07