28/03/2020 Energy, Work and Power(Senior Class Physics Study by Topics) 28/03/2020 0Comments by Gate Academy Welcome to your Energy, Work and Power(Senior Class Physics Study by Topics) NAME EMAIL PHONE NUMBER 1. 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 2.5 5 0.25 2. Mud thrown on a wall and sticking to it is an example for _____ Perfectly inelastic collision Elastic collision Super elastic collision Inelastic collision 3. For a body moving in a circular path, the work done by the centripetal force is ________ Positive Zero Negative Constant 4. A moving hammer drives a nail into the wood. It has kinetic energy. False True 5. A man of mass 50 kg jumps to a height of 1 m. His potential energy at the highest point is (g = 10 m/s^{2}): 5 J 500 J 50 J 5000 J 6. A car is accelerated on a leveled road and attains a velocity 4 times of its initial velocity. In this process, the kinetic energy of the car. Becomes twice to that of the initial Remains the same Becomes 16 times to that of the initial Becomes four times to that of the initial 7. The kinetic energy of an object will increase the most if you _______________ Double the temperature of the object Double the mass of the object Double the velocity of the object Double the potential energy 8. A bullet fired from a gun can pierce a target due to its ___________ Heat energy Acceleration Mechanical energy Kinetic energy 9. The potential energy of an object is equal to ________ The size of the object compared to its surface area. The force of gravity working on the object. The velocity of the object divided by its mass. The work done on the object to put the object into its current state. 10. Two identical arrows, one with twice the kinetic energy of the other, are fired into a hay bale. The faster arrow will penetrate _____. The same distance as the slower arrow. Four times as far as the slower arrow. More than four times as far as the slower arrow. Twice as far as the slower arrow. 11. For a collision to occur, the actual physical contact is necessary. True False 12. When a body slides against a rough horizontal surface, the work done by friction is _____ Negative Positive Constant Zero 13. Which of the following is NOT a consequence of "The Law of Conservation of Energy"? Potential Energy can never be greater than Kinetic Energy 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 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 energy in a closed system is always constant 14. Collision between two carom coins is an example for ____ Elastic collision Perfectly inelastic collision Oblique collision Inelastic collision 15. An object that has potential energy has this energy because of its ____ Location Speed. Acceleration. Momentum. 16. If an object has kinetic energy, then it also must have ____ Speed Force Acceleration Impulse 17. A machine gun fires 60 bullets per minute, with a velocity of 700m/s. If each bullet has a mass of 50g, find the power developed by the gun. 122W 1225W 122.5W 12250W 18. Which of the following is not a unit for power? Joule – second Watt Horsepower Newton-meter per second 19. An object that has kinetic energy must be _____. At an elevated position. Moving. Falling. At rest. 20. A person jumps to the ground from a platform 10 feet high. Which of the following is true? The person's potential energy at the instant they jump is approximately equal to their kinetic energy the instant they land. The person has more kinetic energy before they jump than after they jump. The person's kinetic energy at the instant they jump is approximately double their potential energy the instant they land. The person has less potential energy at the top of the platform than in the air. 21. 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 30000 N 30 N 300 N 22. 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 100J 150J 50J 23. If you push on a wall with a force of 30 N, then ______________. The wall cannot be forced. The wall moves back 3 cm. The wall pushes on you with a force of 30 N. You are pulled towards the wall. 24. 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}) 400J 2514J 1960J 250J 25. A machine does 2500 J of work in 1 min. What is the power developed by the machine? 42 W 21 W 2500 W 150 W 1 out of 25 Time is Up! Time's up