Welcome to your Energy, Work and Power(Senior Class Physics Study by Topics) NAME EMAIL PHONE NUMBER 1. Which of the following is NOT a consequence of "The Law of Conservation of Energy"? It is not necessary to use Kinematics to discover the velocity of an object accelerated by gravity if you know it's initial Potential Energy and its mass. The Kinetic Energy of a dropped object at the instant it hits the ground is roughly equal to the potential energy of the object at the instant it was dropped The energy in a closed system is always constant Potential Energy can never be greater than Kinetic Energy 2. A block with a mass of m crosses a rough horizontal surface at a constant speed of v. The coefficient of kinetic friction between the block and the surface isµ. How much power must be produced in order to overcome the friction force? mg µg µmg µmgv 3. A moving hammer drives a nail into the wood. It has kinetic energy. True False 4. What happens to the total energy of a moving object if all the applied forces are conserved? It decreases It remains constant The velocity is required to answer this question It increases 5. A motorbike engine can develop a power of 90000 W in order to keep a constant velocity of 30 m/s. What is the pushing force? 3000 N 300 N 30 N 30000 N 6. A truck drives slams on the brakes of a moving truck with a constant velocity v, as a result of his action the truck stops after traveling a distance d. If thedriver had been traveling with twice the velocity, what would be the stopping distance compared to the distance in the first trial? Four times greater Two times greater Half as much One-quarter as much 7. The type of energy possessed by a simple pendulum, when it is at the mean position is: Kinetic + Potential energy Potential energy Sound energy Kinetic energy 8. When an object is lifted 10 meters, it gains a certain amount of potential energy. If the same object is lifted 20 meters, its potential energy is ______. Less. The same Twice as much. Four times as much 9. How many Joules of energy are in one kilowatt-hour? 60 kilojoules 60 J 3.6 megajoules 1 J 10. A gardener pushes a lawn roller through a distance of 20m. If he applies a force of 20kg weight in a direction inclined at 60° to the ground, find the work done by him. (g=9.8m/s^{2}) 250J 2514J 1960J 400J 11. If an object has kinetic energy, then it also must have ____ Speed Impulse Force Acceleration 12. When a light body collides with a massive body at rest _____ The light body Remains at rest No reaction happens The light body rebounds after the collision The massive body rebounds after the collision 13. As an object goes up a hill at constant velocity, which of the following is NOT true? The object's Potential Energy is increasing. The object's speed is constant. The object's Kinetic Energy is decreasing. The object's Kinetic Energy is constant. 14. The momentum of a bullet of mass 20 g fired from a gun is 10 kg.m/s. The kinetic energy of this bullet in kJ will be: 25 5 2.5 0.25 15. An object that has potential energy has this energy because of its ____ Acceleration. Momentum. Speed. Location 16. How much mass is converted into energy per day in Tarapur nuclear power plant operated at 10^{7} kW? 9.6g 2g 9g 10g 17. An object with mass "m" kilograms is suspended "h" meters above the ground by a string. If the string is cut, what will the velocity of the object be at the instant it hits the ground? The square root of 2gh H-2gm One-half the mass squared Two times ghm squared 18. If you have to push a car forward, what are the forces acting on you? The car pushes back on you, gravity pulls you down, the ground pushes up on you, and friction on your shoes pushes forward on you. Your own muscles push you down. Only gravity. No forces act on you. 19. The kinetic energy of an object will increase the most if you _______________ Double the velocity of the object Double the mass of the object Double the potential energy Double the temperature of the object 20. "Power" is defined as ________ The velocity of an object squared The sum of potential and kinetic energy The energy necessary to do work The rate at which work is done 21. A car travels with a constant speed of 15 m/s. The car’s engine produces a 4000 N pushing force in order to keep the speed constant. How much power isdeveloped by the engine? 600 W 60 W 6000 W 60000 W 22. When a body falls freely under gravity, then the work done by the gravity is ________ Positive Zero Negative Infinity 23. A person is holding a bucket by applying a force of 10N. He moves a horizontal distance of 5m and then climbs up a vertical distance of 10m. Find the total work done by him? 200J 50J 100J 150J 24. Collision between two carom coins is an example for ____ Inelastic collision Oblique collision Elastic collision Perfectly inelastic collision 25. When a gas filled in a cylinder fitted with a movable piston is allowed to expand, the work done by the gas is positive. True False 1 out of 25 Time is Up! Time's up