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Work and Machines

Work and Machines. Final Review. Nancy pushed a box with a force of 45 N for 15m. How much work did Nancy do?. Answer. 675J. The force that you apply to a machine is the?. Answer. Input Force.

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Work and Machines

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  1. Work and Machines Final Review

  2. Nancy pushed a box with a force of 45 N for 15m. How much work did Nancy do?

  3. Answer • 675J

  4. The force that you apply to a machine is the?

  5. Answer • Input Force

  6. When casting a fishing pole you need to apply 10N of force. The pole in return will put out 30N of force. Calculate the mechanical advantage of the fishing pole?

  7. Answer • 30N/10N= 3

  8. The mechanical advantage of a machine is the number of times a machine increases…

  9. Answer • The force exerted on the machines

  10. What is the ideal mechanical advantage of an incline plane that is 6.0 m long and 1.5 m high?

  11. Answer • 6.0/1.5= 4.0

  12. An ideal machine would have an efficiency of what?

  13. Answer • 100%

  14. The ideal mechanical advantage for an inclined plane is equal to the length of the inclined plane divided by the what?

  15. Answer • Height

  16. Pulling down on a rope to hoist a sail on a sailboat is an example of a machine that does what?

  17. Answer • Changes the direction over which a force is exerted.

  18. The ideal mechanical advantage of a wheel and axle is equal to the…

  19. Answer • Radius of the wheel divided by radius of axle

  20. If tight, rusty scissors have an efficiency of 50 %, half of your work is wasted do to what?

  21. Answer • Friction

  22. What is the formula used to calculate the efficiency of a machine.

  23. Answer • Output work/inputwork x 100%

  24. A ramp is an example of a simple machine called what?

  25. Answer • Inclined plane

  26. Which of these is an example of a third-class lever?

  27. Answer • Your elbow

  28. If the radius of a doorknob is 6.0 cm and the radius of its inner rob is 2.0 cm, what is the mechanical advantage?

  29. Answer • 6.0/2.0=3

  30. A machine that utilizes two or more simple machines is called a what?

  31. Answer • Compound Machine

  32. You do 5,000 J of work using a sledge hammer. The sledge hammer does 2,000J of work on the spike. What is the efficiency if the sledge hammer?

  33. Answer • 40%

  34. One example of a compound machine is a?

  35. Answer • Bike, car, any thing that uses a variety of simple machines.

  36. Which of the following describes a first class lever?

  37. Answer • -----------/\-------------- • Fulcrum is in the middle

  38. A(n)_________ is a grooved wheel with a rope, chain or cable running along the groove.

  39. Answer • Pulley

  40. Which of the following simple machines is an inclined plan wrapped around a post?

  41. Answer • Screw

  42. If you exert a force of 20 newtons to push a desk 10 m, how much work do you do on the desk?

  43. Answer • 200J

  44. If a pulley is attached to something that doesn’t move, is called what?

  45. Answer • Fixed pulley

  46. The fixed point that a lever pivots around is called the

  47. Answer • Fulcrum

  48. A machine can do any of the following except…..

  49. Answer • Increase work

  50. How does a ramp make it easier to move a heavy object a certain distance?

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