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Chapter 5 Clickers Impulse and Linear Momentum Prepared by Dedra Demaree, Georgetown University © 2014 Pearson Education, Inc. Which of the following statements is NOT a pattern observed in the set of three observational experiments with colliding carts? a) The kinetic energy of the carts remained the same before and after the collision. b) The total mass of the carts remained the same before and after the collision. c) The sum of the products of the mass and velocity of the carts remained the same before and after the collision. d) The color of the carts remained the same before and after the collision. © 2014 Pearson Education, Inc. Which of the following statements is NOT a pattern observed in the set of three observational experiments with colliding carts? a) The kinetic energy of the carts remained the same before and after the collision. b) The total mass of the carts remained the same before and after the collision. c) The sum of the products of the mass and velocity of the carts remained the same before and after the collision. d) The color of the carts remained the same before and after the collision. © 2014 Pearson Education, Inc. Which of the following statements is NOT correct about linear momentum? a) Linear momentum is a vector quantity. b) Linear momentum is conserved in a collision. c) Linear momentum is independent of reference frame. d) Linear momentum is the product of a system object's mass and velocity. © 2014 Pearson Education, Inc. Which of the following statements is NOT correct about linear momentum? a) Linear momentum is a vector quantity. b) Linear momentum is conserved in a collision. c) Linear momentum is independent of reference frame. d) Linear momentum is the product of a system object's mass and velocity. © 2014 Pearson Education, Inc. Jen (50 kg) and David (75 kg), both on rollerblades, push off each other abruptly. After the push, Jen has a velocity of -3.0 m/s. What is David's velocity? a) b) c) d) +2.0 m/s +3.0 m/s +4.5 m/s Not enough information is given to determine David's velocity. © 2014 Pearson Education, Inc. Jen (50 kg) and David (75 kg), both on rollerblades, push off each other abruptly. After the push, Jen has a velocity of -3.0 m/s. What is David's velocity? a) b) c) d) +2.0 m/s +3.0 m/s +4.5 m/s Not enough information is given to determine David's velocity. © 2014 Pearson Education, Inc. Two identical carts travel toward each other at the same speed and collide with each other. What can we conclude? a) The final linear momentum of the two carts will sum to zero. b) The carts will have zero velocity after the collision. c) After the collision, the carts will be moving with the same speed but in opposite directions. d) We cannot reach any of these conclusions. © 2014 Pearson Education, Inc. Two identical carts travel toward each other at the same speed and collide with each other. What can we conclude? a) The final linear momentum of the two carts will sum to zero. b) The carts will have zero velocity after the collision. c) After the collision, the carts will be moving with the same speed but in opposite directions. d) We cannot reach any of these conclusions. © 2014 Pearson Education, Inc. A 1000-kg car is moving at 10 m/s with respect to the ground when the car hits a barrier. The car is stopped in 0.5 s by the force of the barrier on the car. What is the magnitude of the average force the barrier exerted on the car during the collision? a) b) c) d) 2000 N 5000 N 20,000 N Impossible to determine from the information given © 2014 Pearson Education, Inc. A 1000-kg car is moving at 10 m/s with respect to the ground when the car hits a barrier. The car is stopped in 0.5 s by the force of the barrier on the car. What is the magnitude of the average force the barrier exerted on the car during the collision? a) b) c) d) 2000 N 5000 N 20,000 N Impossible to determine from the information given © 2014 Pearson Education, Inc. Consider the happy ball and the sad ball. If dropped from a height h, the sad ball does not bounce and the happy ball bounces back to its original height. Which of the following statements is NOT correct? a) The final momentum of the sad ball is zero. b) The final momentum of the happy ball is equal in magnitude to its initial momentum. c) The change in the momentum of the sad ball is larger than the change in the momentum of the happy ball. d) The impulse exerted on the happy ball is greater than the impulse exerted on the sad ball. © 2014 Pearson Education, Inc. Consider the happy ball and the sad ball. If dropped from a height h, the sad ball does not bounce and the happy ball bounces back to its original height. Which of the following statements is NOT correct? a) The final momentum of the sad ball is zero. b) The final momentum of the happy ball is equal in magnitude to its initial momentum. c) The change in the momentum of the sad ball is larger than the change in the momentum of the happy ball. d) The impulse exerted on the happy ball is greater than the impulse exerted on the sad ball. © 2014 Pearson Education, Inc. Consider the happy ball (mh) and the sad ball (ms). If dropped from a height h, the sad ball does not bounce and the happy ball bounces back to its original height. Which of the following equations is NOT correct? (Take "up" to be the positive axis.) a) b) c) d) e) ms(-vi) + Js = 0 mh(-vi) + Jh = mh(+vf) ms(-vi) = mh(-vi) |mh(-vi)| = |mh(+vf)| They are all correct. © 2014 Pearson Education, Inc. Consider the happy ball (mh) and the sad ball (ms). If dropped from a height h, the sad ball does not bounce and the happy ball bounces back to its original height. Which of the following equations is NOT correct? (Take "up" to be the positive axis.) a) b) c) d) e) ms(-vi) + Js = 0 mh(-vi) + Jh = mh(+vf) ms(-vi) = mh(-vi) |mh(-vi)| = |mh(+vf)| They are all correct. © 2014 Pearson Education, Inc. Consider the happy ball (mh) and the sad ball (ms). If dropped from a height h, the sad ball does not bounce and the happy ball bounces back to its original height. Which of the following equations is NOT correct? (Take "up" to be the positive axis.) a) b) c) d) |Js| = |ms(-vi)| |Jh| = |2mh(-vi)| |Jh| = 2|Js| They are all correct. © 2014 Pearson Education, Inc. Consider the happy ball (mh) and the sad ball (ms). If dropped from a height h, the sad ball does not bounce and the happy ball bounces back to its original height. Which of the following equations is NOT correct? (Take "up" to be the positive axis.) a) b) c) d) |Js| = |ms(-vi)| |Jh| = |2mh(-vi)| |Jh| = 2|Js| They are all correct. © 2014 Pearson Education, Inc. Based on the impulse applied to each ball and Newton's third law, which ball will apply a bigger impulse to an object it hits? a) The happy ball will apply the larger impulse. b) The happy ball and the sad ball will apply the same impulse. c) The sad ball will apply the larger impulse. © 2014 Pearson Education, Inc. Based on the impulse applied to each ball and Newton's third law, which ball will apply a bigger impulse to an object it hits? a) The happy ball will apply the larger impulse. b) The happy ball and the sad ball will apply the same impulse. c) The sad ball will apply the larger impulse. © 2014 Pearson Education, Inc. An impulse-momentum bar chart describes the following situation: A bullet is fired horizontally into a block of wood resting on a table. Immediately after the bullet joins the block, the block and the bullet move together in the positive x-direction. Which equation is correct? a) b) c) d) e) mBvBi + mwvwi + J = mBvBf + mwvwf mBvBi + 0 + 0 = mBvBf + mwvwf mBvBi + mwvwi + J = (mB + mw)vf mBvBi + 0 + 0 = (mB + mw)vf They are all correct. © 2014 Pearson Education, Inc. An impulse-momentum bar chart describes the following situation: A bullet is fired horizontally into a block of wood resting on a table. Immediately after the bullet joins the block, the block and the bullet move together in the positive x-direction. Which equation is correct? a) b) c) d) e) mBvBi + mwvwi + J = mBvBf + mwvwf mBvBi + 0 + 0 = mBvBf + mwvwf mBvBi + mwvwi + J = (mB + mw)vf mBvBi + 0 + 0 = (mB + mw)vf They are all correct. © 2014 Pearson Education, Inc. A 50-kg stunt diver is falling at a speed of 20 m/s when she is stopped by sinking into a cushion that exerts an average force of 500 N on her. How much time did it take her to stop moving once she hit the cushion? a) b) c) d) 0.5 second 1.0 seconds 2.0 seconds 5.0 seconds © 2014 Pearson Education, Inc. A 50-kg stunt diver is falling at a speed of 20 m/s when she is stopped by sinking into a cushion that exerts an average force of 500 N on her. How much time did it take her to stop moving once she hit the cushion? a) b) c) d) 0.5 second 1.0 seconds 2.0 seconds 5.0 seconds © 2014 Pearson Education, Inc. Which of the following is NOT an assumption we need to make to solve jet propulsion problems without calculus? a) We need to assume the jet is moving through air. b) We need to assume the fuel burns very quickly. c) We need to assume there is negligible change in mass during the thrust. d) We need to assume all of the above. © 2014 Pearson Education, Inc. Which of the following is NOT an assumption we need to make to solve jet propulsion problems without calculus? a) We need to assume the jet is moving through air. b) We need to assume the fuel burns very quickly. c) We need to assume there is negligible change in mass during the thrust. d) We need to assume all of the above. © 2014 Pearson Education, Inc. Which of the following statements is NOT true about applying the impulse-momentum principle to two-dimensional collisions? a) If the impulse is zero, the magnitude of the system's initial momentum equals the magnitude of its final momentum. b) If the impulse is zero, the system's initial momentum along the x-axis equals its final momentum along the x-axis. c) If the impulse is zero, the system's initial momentum along the y-axis equals its final momentum along the y-axis. © 2014 Pearson Education, Inc. Which of the following statements is NOT true about applying the impulse-momentum principle to two-dimensional collisions? a) If the impulse is zero, the magnitude of the system's initial momentum equals the magnitude of its final momentum. b) If the impulse is zero, the system's initial momentum along the x-axis equals its final momentum along the x-axis. c) If the impulse is zero, the system's initial momentum along the y-axis equals its final momentum along the y-axis. © 2014 Pearson Education, Inc.