28A book is lifted a distance of 3.5 meters above the surface of the Earth. The change in potential energy is 300 Joules, what is the mass of the book? 29. What is the equation for elastic potential energy? 30. What does k stand for? What does x stand for? 31A spring has a spring constant of 200 N/m. How much potential energy is stored in a spring that is stretched from a position of 0.5 meters to 2.0 meters? 32. What does it mean to say something is conserved? 33. What happens to potential energy as an egg falls? 34. What is the rate at which work is done called? 35. What are the two equations for power? 36. What are the units for power? 37.11 25 kg box is lifted a distance of 10 meters by a force of 50 N. The box was lifted in 16 seconds. What work was done on the box by the lifting force? What power was needed to lift the box? 22.A 13 kg box starts at a velocity of 10 m/s. After being pushed a distance of 22 meters it has a velocity of 20 m/s. What force was pushing the box? 23. What is energy in your body usually stored as? 24. What is the definition of potential energy? 25. The equation for gravitational potential energy is PEg = mgh. What does m stand for? What does g stand for? What does h stand for? 26.What is the potential energy of a 5kg book that is 2.5 meters above the surface of the Earth? 27.What is the change in potential energy of a 5 kg book that is lifted from a height of 2 meters above the ground to a height of 7 meters? 9. How much work is done on a vacuum cleaner pulled 4.0 meters by a force of 50 N at an angle of 300 above the horizontal? 10.A block is pushed to the right with a force of 120 N while friction acts in the opposite direction with a force of 100 N. The block was pushed a distance of 5.0 meters. How much work was done by the pushing force? How much work was done by friction? 11.An object has a weight of 50 N. You lift the object at a constant velocity upwards a distance of 5 meters. How much work did you do on the object? How much work did the force of gravity do on the object? 17.A 50 gram ball is moving with a speed of 20 m / 5. What is the kinetic energy of the ball? 18.A car has 20,000 I of kinetic energy. [fits velocity is 25 m/s what is its mass? 19.A runner has 3000 ] ofkinetic energy. If the mass of the runner is 50 kg what is the velocity of the runner? 20. What is the work-kinetic energy theorem? 21.A 5 kg box is pushed across a horizontal frictionless surface with a constant force of 50 N. If the box starts from rest and is pushed a distance of 10 meters what is the nal velocity of the box