Chapter 21 Test: Force and Momentum

Chapter 21 Test: Force and MomentumID AShort AnswerYou must use complete sentences to answer each question to get full credit.**Example of a Complete Sentence Answer**Both cars do or do not have the same velocity because…36. You are in a car going 70 km/h and another car passes you going in the opposite direction at 70 km/h. Doboth cars have the same velocity? Explain. 3pts37. If someone is walking on a moving bus, name two reasonable reference points you might use to describehis or her motion. 3pts38. What is the difference between distance and displacement? 3pts39. If you ride your bike around the block, returning to the exact point where you started, what is yourdisplacement? 2pts40. Describe your motion in terms of velocity as you ride down the street, come to a red light, wait for thegreen light and then start off again. 5pts41. Describe the motion of a car with an acceleration of –2 m/s 2 . 2pts42. Is the momentum of a car traveling south the same as the momentum of a similar car traveling north at thesame speed? Explain. 3pts43. A truck and a bicycle have the same momentum. Which would be harder to stop? Explain. 3pts44. When three balls collide, they bounce off of each other and roll away, but eventually they stop. Does thisviolate the law of conservation of momentum? Explain. 3ptsProblemsYou must write the formula first, substitute for the variables second, solve third, put correct units fourth,and add direction or “+” or “-“ last. The last step is only necessary for certain problems.**Example of Full Credit Response**Step 1: v=d/tStep 2: v=10m/5sStep 3: v=2 m/s, west45. You travel 190 km in 2 h. What is your speed in km/h? (v=d/t) 4pts46. A car goes from 80 km/h to 20 km/h in 0.5 h. What is the acceleration in km/h 2 ? (a=(v f -v i ) / t) 5pts47. A compact car with a mass of 725 kg is moving at 30 m/s. What is its momentum? (p=mv) 4pts48. A 50-kg object has a momentum of 600 kg x m/s moving to the North. What is its velocity? (p=mv) 5pts49. A 50-kg object moving at 12 m/s has a momentum of 600 kg × m/s. What is the mass of an object,moving at 4 m/s that has the same momentum? (p=mv) 4pts50. A 25-kg object moving at 15 m/s collides with a 15-kg object that is standing still. They stick together andkeep moving to the East. What is the final velocity? (m 1 v 1 =m 2 v 2 ) 5pts

ID A