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Unit IX: Worksheet 1 1. Two objects, A & B, have identical velocities. Object A has 3 times the mass of object B. Compare the momentum of each object. Justify your answer. Pa = 3Pb < 13 m 3 mv m my 2. Two other objects, C and D, have identical masses. Object C has twice the velocity of object D. Compare the momentum of each object. Justify your answer. PC = 2 Pd< 2v m / 2 mv m mv 3. While being thrown, a net force of 132 N acts on a baseball (mass = 140g) for a period of 4.5 x 10"sec. What is the magnitude of the change in momentum of the ball? J = AP ( 135 ) ( - 15 ) = AP F = 132 N 5. 94 N.S = 5, 94 Kam t =.45s 41 15 X10., 25 4. If the initial speed of the baseball in question 3 is vo = 0.0 m/s, what will its speed be when it leaves the pitcher's hand? AP = P2-PI 5. 94= (. 14) ( V 2- 0) 5 . 94 = muz - mu, 412. 40 = 5. 94 = V2 5. 94 = m ( v 2 - vi ) . 14 5 . When the batter hits the ball, a net force of 1320 N, opposite to the direction of the ball's initial motion, acts on the ball for 9.0 x 10" s during the hit. What is the change in momentum of the ball? What is the final velocity of the ball? F At = impluse = momentum = mav 1320 N * ( 9. 0 x 10- 35) = 11. 88 N - S= (0. 140 kg ) Av Av = 84.9 m/S= VF-vi = 84.9 m/s = vf- (- 42.4m/s)= 42.5 m/s 6. What force does the ball exert on the bat in the question above? Explain. N 3rd law: bat on ball= -F ball on bat = 1320 N= - 1-13201