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Physical Science 3rd Nine Week Study Guide 1. ___ is the change of position of a body. ___ is the measure of how far an object moved. ____ is the distance and direction of an object’s change in position from the starting point. 2. ____ is the distance an object travels per unit of time. 3. ____ includes the speed of an object and the direction of its motion. 4. ____ is the rate of change of velocity. 5. When two or more forces act on an object at the same time, the forces combine to form the ____. 6. Forces on an object that are equal in size and opposite in direction are called ____. 7. ____ is the tendency of an object to resist any change in its motion. 8. ____ states that an object moving at constant velocity keeps moving at that velocity unless an unbalanced net force acts on it. It is also called the ____. 9. What are the units for the following? Acceleration: ____; speed ____; velocity ____; force ____ 10. ____ states that the acceleration of an object is the same direction as the net force on the object. It can be calculated from the following equation: _____. 11. ____ is the force that oppose the sliding motion of two surfaces that are touching each other. 12. ____ is the friction-like forces that opposed the motion of objects that move through the air. 13. ____ is the attractive force between any two objects that depends on the masses of the objects and the distance between them. 14. The gravitational force exerted on an object is called the object’s ____. 15. What is a heat mover? 16. Acceleration towards the center of a curved or circular path is called ____. 17. The net force exerted toward the center of a curved path is called a ____. 18. ____ states that for every action force there is an equal and opposite reaction force. 19. ____ is the energy a moving object has because of its motion. 20. Stored energy due to position is called ____. 21. ____ is energy stored by objects due to their position above Earth’s surface. 22. ____ is the total amount of potential and kinetic energy in a system. 23. The ____ states that energy cannot be created or destroyed. 24. ____ is the transfer of energy that occurs when a force makes an object move. 25. ____ is the amount of work done in one second. 26. A ____ is a device that makes doing work easier. 27. ____ is a measure of how much of the work put into a machine is changed into useful output work by the machine. 28. The ____ is a measure of the average kinetic energy of the particles in the object. 29. The sum of the kinetic and potential energy in all of the particles in an object is ____. 30. ____ is thermal energy that flows from something at a higher temperature to something at a lower temperature. 31. ____is the transfer of thermal energy by collisions between particles in matter. ____ is the transfer of thermal energy in a fluid by the movement of warmer and cooler fluid from place to place. ____ is the transfer of energy by electromagnetic waves (radiant energy). 32. What are the units for the following? Energy ____; work ____; power ____ True or False 33. If a person tries to lift a heavy box for 5 seconds and can’t make it budge, the work done on the box is equal to the amount of energy the person uses. 34. Machines decrease the amount of energy that is needed to do work. 35. All objects produce different types of electromagnetic waves depending on the object’s temperature. 36. Energy is transferred as heat from a substance at high temperature to a substance at low temperature. 37. Heating by convection can occur through solids, liquids, or gases. 38. When a refrigerant evaporates, it adds energy as heat to its surroundings. 39. When the same amount of force is applied to two different masses, the smaller mass will be accelerated at the same rate as the larger mass. 40. Energy as heat flows from a lower temperature to a higher temperature. 41. If the net force acting on a stationary object is zero, then the object will remain at rest. 42. On a distance-time graph, a single point tells the average speed. Problems 43. An ant travels 0.75 m in 3 s. What is the ant’s speed? 44. It takes a car 65 s to go from rest to 35 m/s. What is the acceleration of the car? 45. A 73 kg mass has an acceleration of 4.9 m/s2. What is the net force applied? 46. What is the kinetic energy of a 3 kg object moving at 4 m/s? 47. If you have a mass of 56 kg and you are standing on a platform 1.5 m above ground, what is your gravitational potential energy? 48. When moving a couch, you exert a force of 375 N and push it 3.5 m. How much work do you do? 49. What is the power developed by a machine to perform 695 J of work in 20 s? 50. A machine has an output work of 140 J and an input work of 230 J. What is the efficiency? 51. Calculate the mechanical advantage of a hammer if the input force is 115 N and the output force is 1700 N. Answer Key 1. motion; distance; displacement 2. speed 3. velocity 4. acceleration 5. net force 6. balanced forces 7. inertia 8. Newton’s 1st law; law of inertia 9. m/s2; m/s; m/s; N 10. Newton’s 2nd law; F = ma 11. friction 12. air resistance 13. gravity 14. weight 15. A device that does work to move heat from a cooler temperature to a warmer temperature 16. centripetal acceleration 17. centripetal force 18. Newton’s 3rd law 19. kinetic energy 20. potential energy 21. gravitational potential energy 22. mechanical energy 23. law of conservation of energy 24. work 25. power 26. machine 27. efficiency 28. temperature 29. thermal energy 30. heat 31. conduction; convection; radiation 32. J; J; W 33. false 34. false 35. true 36. true 37. false 38. false 39. false 40. false 41. true 42. false 43. speed = 0.25 m/s 44. acceleration = 0.54 m/s2 45. force = 357.7 N 46. kinetic energy = 24 J 47. GPE = 823.2 J 48. work = 1312.5 J 49. power = 34.75 W 50. efficiency = 60.9 % 51. MA = 14.8