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Bell Work 4/25/12 – 6 min

Bell Work 4/25/12 – 6 min. A 30.0 lb monkey climbs 22.0 foot up a tree in 5.00 s. What is his weight in N? How many meters of tree did he climb? How much work did he do? What was his power in Watts? What was his power in horsepower?

sarah-cash
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Bell Work 4/25/12 – 6 min

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  1. Bell Work 4/25/12 – 6 min • A 30.0 lb monkey climbs 22.0 foot up a tree in 5.00 s. • What is his weight in N? • How many meters of tree did he climb? • How much work did he do? • What was his power in Watts? • What was his power in horsepower? • How would carrying a bag of bananas have affected the amount of work he did? Power?

  2. Bell Work 5/9/13 – 5 min Another word for input is _____. Other words for output are _____ and _____. A first class lever consists of __, __, then __. A second class lever consists of __, __, then __. A third class lever consists of __, __, then __. Identify the class of the following levers. (some are >1 lever)a. Crowbar b. Bottle openerc. Seesaw d. Wrench e. Nail clippers f. Mousetrap

  3. Bell Work 5/1/12 – 5 min Another word for load is _____. Another word for effort is _____. To identify the type of lever something is, you look at what is in the middle. A first class lever has the _____ in the middle. A second class lever has the _____ in the middle. A third class lever has the _____ in the middle. Identify the class of the following levers.a. Fishing rodb. scissors c. salad tongs Turn in missing work by tomorrow, take a zero, or make other arrangements.

  4. Bell Work 5/7/12 – 4 minutes Identify the type of lever, find the mechanical advantage, and find the missing force.

  5. Bell Work 5/4/12 – 4 minutes Identify the type of lever, find the mechanical advantage, and find the missing force.

  6. Bell Work 5/8/12 – 5 min Bill (88.0 kg) climbs the 12.0 m wall in 55.0 s. His twin brother Bart (88.0 kg) runs up the steps in 20.0 s. Calculate Bill’s work & power. Calculate Bart’s work & power.

  7. Bell Work 5/9/13 – 5 min Another word for input is _____. Other words for output are _____ and _____. A first class lever consists of __, __, then __. A second class lever consists of __, __, then __. A third class lever consists of __, __, then __. Identify the class of the following levers. (some are >1 lever)a. Wheelbarrow b. Rakec. Seesaw d. Golf Club e. Shovelf. Nail clippers

  8. Today you are going to…take notes on the simple machines So you can…calculate the estimated & actual mechanical advantage You’ll know you’ve got it when you can • Answer the questions at the end of class

  9. Machines can do 3 things • Change direction of force • Increase force & decrease distance • Decrease force & increase distance

  10. Mechanical advantage – how much machine multiplies force or increases distance • Ratio between output force and input force • OR • input distance and output distance • >1 1 multiplies input force, < 1multiples distance & speed

  11. Simple Machines • Simple machines – most basic machines • 6 types • 3 in lever family • Simple levers (3 classes!) • Pulleys • Wheel & axle • 3 in inclined plane family • Simple inclined Plane • Wedge • Screw

  12. 1. Simple Levers 3 parts of a lever: Input, fulcrum, & output Input (aka effort) – force you’re applying Fulcrum – pivot point, doesn’t move Output (aka load, resistance) – what you’re lifting 3 classes of levers depending on location of input, fulcrum, & output

  13. 1st Class Lever • 1st IFO – fulcrum in middle • Most common type • May increase force or distance depending on location of fulcrum • Always changes direction • Sea saw, hammer • Pliers – 2 1st class levers put together

  14. 2nd Class Lever • 2nd FOI – Output • Increases force, decreases distance • Wheelbarrow, nutcrackers, hinged doors

  15. 3rd Class Lever • 3rd FIO • Increases distance object is moved, decreases force • Fishing rod, forearm

  16. Estimated Mechanical Advantage of Levers Identify the type of lever, find the mechanical advantage, and find the missing force.

  17. Mechanical Advantage of Levers Identify the type of lever, find the mechanical advantage, and find the missing force.

  18. Mechanical Advantage of Levers Identify the type of lever, find the mechanical advantage, and find the missing force.

  19. Mechanical Advantage of Levers Identify the type of lever, find the mechanical advantage, and find the missing force.

  20. Mechanical Advantage of Levers Identify the type of lever, find the mechanical advantage, and find the missing force.

  21. 1. Simple Levers • 1st Class OFA – Fulcrum in middle • Most common type • Sea saw, crowbar • Pliers – 2 1st class levers put together • 2nd FOA – output (load) in middle • Increases force, decreases distance • nutcrackers, hinged doors, wheelbarrow • 3rd FIO – input (effort) in middle • Increases distance object is moved, decreases force • forearm, baseball bat, hockey stick, rake

  22. Pulley • Modified levers • Middle of pulley is fulcrum of lever • Single fixed pulley mechanical advantage of 1 – both sides of lever same length • Changes direction of force

  23. Pulley • Using more than 1 pulley at a time increases mechanical advantage • Block and tackle – several pulleys put together in single unit

  24. 2. Pulleys • Modified levers • Center of pulley is fulcrum of lever • Single fixed pulley mechanical advantage of 1 – both sides of lever same length • Changes direction of force • Using more than 1 pulley at a time increases mechanical advantage • Block and tackle - several pulleys put together in single unit

  25. 3. Wheel & Axle • Lever/pulley connected to shaft • Steering wheel of car, screwdriver, crank • Multiples force (or distance)

  26. 3. Wheel & Axle • made up of two circular objects of different sizes • axle (a rod) attached to the center of a larger wheel

  27. 3. Wheel & Axle • two machines in one because you can use each part in different ways. • roll something along wheels cut down on friction • Generally, the bigger the wheel = easier to roll • like a “lever in the round” • door knob, sink faucet handle are round levers • fulcrum is in the middle where the axle turns

  28. Larger wheel diameter  less force needed  • Larger wheel diameter  have to turn further 

  29. Wheel and Axle • MA = Radius of wheel or = diameter of wheel Radius of axle diameter of axle

  30. D.J. uses a crowbar to move a 600 N Dom. The effort arm is 80 cm long and the arm is 15 cm long. What type of lever is this? What is the mechanical advantage?

  31. Inclined plane • a ramp used to reduce the effort needed to raise or lower an object • How can he make it take less force? • MA =

  32. Bell Work 5/9/12 – 5 minutes Find type & mechanical advantage.

  33. Rank from least to greatest MA

  34. Wedge • Wedge - simple machine used to separate objects (or hold them together) • made up of one or two inclined planes that meet & form sharp edge • Difference between wedge & inclined plane: • Wedge moves, inclined plane doesn’t • Effort force applied in different directions • a sharper wedge yields a larger force. • Ex: knives, axes, forks and nails

  35. Wedge • Thinner, more mechanical advantage • How could you increase the MA of an ax or knife? • Sharpen it!

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