STATS 101 Answers to Chapter 12 study guide 2020 - University of Colorado | STATS101 Answers to Chapter 12 study guide 2020

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STATS 101 Answers to Chapter 12 study guide 2020 - University of Colorado Chapter 12 review sheet. Name______________________________ 1. What are the 4 kinds of friction? Static, slidin... g, rolling, fluid. 2. What is the SI unit for force? newton 3. What happens when an unbalanced force acts on an object? A balanced force? Unbalanced The object’s motion is changed. Balanced  The object’s motion remains the same. 4. What property of matter resists change in motion? Inertia 5. What 2 forces cause a projectile to follow a curved path? The applied force and gravity. 6. What is Newton’s 2nd law of motion? f= m●a Rearrange the formula for newton’s second law to solve for acceleration. a= f/m For mass. m=f/a 7. What is Newton’s 3rd Law of motion? For every action there is an equal and opposite reaction. 8. In a closed system, what is conserved when 2 objects collide? Momentum 9. What is Impulse? Impulse is equal to the CHANGE in an object’s momentum. Impulse is calculated by multiplying force by time. w=mg g=9.8m/s2 momentum= mv m1v1 = m2v2 10. 2nd Law: A tow truck exerts a net horizontal force of 1060 N on 658-kilogram car. What is the acceleration of the car during this time? Show your work. a = 1.61 m/s2 11. 2nd Law: A small engine causes a 1.2-kg model airplane to accelerate at a rate of 5 m/s2. What is the net force on the model airplane? Show your work. f= 6 N 12. A 36 kilogram canoe broke free of its dock and is now floating downriver at a speed of 2.1 m/s. What is the canoe’s momentum? Show your work. Momentum = 75.6 13. A car is traveling at a speed of 85 km/hr and has a mass of 900kg. What is the car’s momentum? Show your work. Momentum = 76,500 14. Elastic collision. A green ball with a mass of 75 grams is traveling at a speed of 2 m/s and strikes a red ball. What is the speed of the second ball? Velocity of red ball = 2 m/s 15. Inelastic collision. A bullet with a mass of 7 grams and a speed of 750 m/s is fired into a holiday jell-o mold with a mass of 2000g. What is the speed of the jell-o after the collision? Velocity of jello/bullet combo = 2.62 m/s 16. Inelastic collision. A squirrel with a mass of 250 gram travelling 10m/s jumps onto a little red wagon with a mass of 3000 grams. What is the speed of the squirrel/wagon combo? Velocity of squirrel/wagon combo = .77 m/s 17. Draw a free body diagram representing an apple falling to the ground. - - - - - - - - -- - - - - - - - - - - - - - - - - - - - - - - 27. Momentum of a system is conserved only when a. there are no internal forces acting on the system. b. the system is not moving. c. there are no forces acting on the system. d. there is no net external force acting on the system. ____ 28. A collision is considered elastic if a. there is no lasting deformation. b. the objects don’t stick together. c. the objects that collide don't get warmer. d. after the collision, the objects have the same shape as before the collision. e. all of the above ____ 29. Which of the following has the largest momentum? a. A large truck parked in a parking lot b. A tightrope walker crossing Niagara Falls c. The science building at your school d. A pickup truck traveling down the highway e. A dog running down the street ____ 30. A cannon recoils from launching a cannonball. The speed of the cannon's recoil is small because the a. impulse on the cannon is less than the impulse on the cannonball. b. cannon has far more mass than the cannonball. c. momentum of the cannon is unchanged. d. force against the cannon is relatively small. e. none of the above ____ 31. In order to catch a ball, a baseball player moves his or her hand backward in the direction of the ball's motion. Doing this reduces the force of impact on the player's hand principally because a. the time of impact is decreased. b. the time of impact is increased. c. the velocity of the hand is reduced. d. the momentum of impact is reduced. e. none of the above ____ 32. Superman is at rest in space when he throws an asteroid that has more mass than he does. Which moves faster, Superman or the asteroid? a. Superman b. The asteroid c. They both move at the same speed. [Show More]

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