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Warm-UP your brain!

Warm-UP your brain!. To help rearrange the furniture in your classroom, you exert a force of 20 N to push a desk 10 m. How much work do you do? If it takes you 5 seconds to move the desk, how much power do you produce? Place answers on a note card and place the note card in the fish bowl!.

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Warm-UP your brain!

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  1. Warm-UP your brain! To help rearrange the furniture in your classroom, you exert a force of 20 N to push a desk 10 m. How much work do you do? If it takes you 5 seconds to move the desk, how much power do you produce? Place answers on a note card and place the note card in the fish bowl!

  2. To help rearrange the furniture in your classroom, you exert a force of 20 N to push a desk 10 m. How much work do you do? Work = Force x distance W = 20 N x 10 m W = 200 Nm = 200 joules

  3. 2. If it takes you 5 seconds to move the desk, how much power do you produce? P = W = F x d t t P = 20 N x 10 m 5 s P = 200 joules 5 s P = 40 joules  second = 40 watts

  4. Practice Sheet #15 Review • A carpenter lifts a 400-N beam a distance of 1.2 meters. How much work is done on the beam? • Find ____________ Formula _____________________ • Given: Apply:

  5. Practice Sheet #15 Review • A carpenter lifts a 400-N beam a distance of 1.2 meters. How much work is done on the beam? • Find _WORK___ Formula __W = F x d_____ • Given: Apply: F = 400N d = 1.2 m W = 400 N x 1.2 m W = 480 Nm = 480 joules Joules is abbreviated with J

  6. Practice Sheet #15 Review • A dancer lifts a 200-N ballerina overhead a distance of 1.4 meters. How much work is done during the lift? • Find _WORK___ Formula __W = F x d_____ • Given: Apply: F = 200 N d = 1.4 m W = 200 N x 1.4 m W = 280 J

  7. Practice Sheet #15 Review • Tom uses a 150-N force to try and move a bookcase from one wall in his library to another wall. Unfortunately Tom cannot move the bookcase. How much work does Tom do? • Find _WORK___ Formula __W = F x d_____ • Given: Apply: W = 150 N x 0 m W = 0 J NO Work was done! F = 150 N d = 0 m

  8. Practice Sheet #15 Review • A motor exerts a force of 10,000 N to lift an elevator 6m in 5 seconds. What is the power produced by the motor? • Find _Power___ Formula __________________ • Given: Apply:

  9. Practice Sheet #15 Review • A motor exerts a force of 10,000 N to lift an elevator 6m in 5 seconds. What is the power produced by the motor? • Find _Power___ Formula __P = (F x d) / t_____ • Given: Apply: P = (10,000 N x 6 m) 5 s P = 12,000 Nm s P = 12,000 watts or 12 kw F = 10,000 N d = 6 m t = 5 s

  10. Practice Sheet #15 Review • A tow truck exerts a force of 9,000 N to pull a car out of a ditch. It moves the car a distance of 6 m in 25 seconds. What is the power of the tow truck? • Find _Power___ Formula __P = (F x d) / t_____ Given: Apply: P = 9,000 N x 6 m 25 s P = 2160 watts F = 9,000 N d = 6 m t = 25 s

  11. Practice Sheet #15 Review • 6. Fill in the Blank: Complete each statement using a term from the list below. • Distance joules Work • Force W= F x d • Work needs two things: __________________ and ______________. • The formula for work is ____________________________________. • If there is no movement, there can be no ______________________. • Work is measured in ______________________________________.

  12. Practice Sheet #15 Review • 6. Fill in the Blank: Complete each statement using a term from the list below. • Distance joules Work • Force W= F x d • Work needs two things: _Distance___ and __Force__. • The formula for work is ____________________________________. • If there is no movement, there can be no ______________________. • Work is measured in ______________________________________.

  13. Practice Sheet #15 Review • 6. Fill in the Blank: Complete each statement using a term from the list below. • Distance joules Work • Force W= F x d • Work needs two things: _Distance___ and __Force__. • The formula for work is __W = F x d____. • If there is no movement, there can be no ______________________. • Work is measured in ______________________________________.

  14. Practice Sheet #15 Review • 6. Fill in the Blank: Complete each statement using a term from the list below. • Distance joules Work • Force W= F x d • Work needs two things: _Distance___ and __Force__. • The formula for work is __W = F x d____. • If there is no movement, there can be no _work_____. • Work is measured in ______________________________________.

  15. Practice Sheet #15 Review • 6. Fill in the Blank: Complete each statement using a term from the list below. • Distance joules Work • Force W= F x d • Work needs two things: _Distance___ and __Force__. • The formula for work is __W = F x d____. • If there is no movement, there can be no _work_____. • Work is measured in __joules__________.

  16. Practice Sheet #15 Review • 7. Fill in the Blank: Complete each statement using a term from the list below. • Distance Force P = F x d • Time Watts t • Power needs three things: __________________ , ____________________ and ____________________. • The formula for power is ____________________________________. • Power is measured in ______________________________________.

  17. Practice Sheet #15 Review • 7. Fill in the Blank: Complete each statement using a term from the list below. • Distance Force P = F x d • Time Watts t • Power needs three things: __Distance_ , ___Time__ and __Force____. • The formula for power is ____________________________________. • Power is measured in ______________________________________.

  18. Practice Sheet #15 Review • 7. Fill in the Blank: Complete each statement using a term from the list below. • Distance Force P = F x d • Time Watts t • Power needs three things: __Distance_ , ___Time__ and __Force____. • P = F x d • The formula for power is ___________t___. • Power is measured in ______________________________________.

  19. Practice Sheet #15 Review • 7. Fill in the Blank: Complete each statement using a term from the list below. • Distance Force P = F x d • Time Watts t • Power needs three things: __Distance_ , ___Time__ and __Force____. • P = F x d • The formula for power is ___________t___. • Power is measured in ___Watts_.

  20. Recall from yesterday, the scientific definition of work: Work is the transfer of energy through a distance W=F x d

  21. A machine is a device that makes your task easier! In general, machines allow you to overcome gravity, inertia, and/or friction in order to move something!

  22. A machine is any device that can change the strength of a force, its speed, or its direction, but a machine does not reduce the amount of work to be done.

  23. Machines! • Machines make work easier by changing: • The size of the force • The direction of the force • Both the size and direction of a force

  24. Machines! Two types of forces are involved with machines: Resistance (Output Force) – the weight of the object to be moved Effort (Input Force) – the force that moves the resistance

  25. Mechanical Advantage The number of times a machine multiples the effort force is the mechanical advantage (MA) of the machine. MA = resistance effort

  26. Example #5 Example #5: An inclined plane lets you move a 10-Newton weight (resistance) with an effort force of 5-Newtons. What is the mechanical advantage of the inclined plan? M.A.= resistance effort = 10 = 2 5 This means that the inclined plane doubles the effort

  27. Mechanical Advantage and Work Different machines have different mechanical advantages. Remember no matter what the mechanical advantage is, the amount of work is the same!

  28. Simple Machine A simple machine is a device that does work with only one movement.

  29. LEVERS

  30. Definition of a Lever A lever is a bar that is free to pivot, or turn, about a fixed point, the fulcrum.

  31. Pulleys A pulley works something like a lever. Instead of a bar, a pulley has a rope.

  32. Wheel and Axle A wheel and axle is a simple machine consisting of two wheels of different sizes that rotate together.

  33. Inclined Plane A inclined plane makes it easier to lift something from a lower level to a higher level.

  34. Screw A inclined plane wrapped around a center core.

  35. Wedge Looks like two inclined planes placed back-to-back.

  36. Simple Machine • 1. Lever • 2. Pulley • 3. Wheel and Axle • Inclined Plane • Screw • Wedge

  37. Today's Review Please do not turn on your iResponse devices until instructed to do so.

  38. 1. Simple machine does work with iRespond Question Multiple Choice F A.) only one motion B.) electricity C.) at least two motions D.) E.)

  39. iRespond Question Multiple Choice F 2. In general, machines allow you to ________________________ in order to move something! A.) overcome gravity B.) overcome friction C.) overcome inertia D.) all of the above E.)

  40. iRespond Question Multiple Choice F 3. A machine is any device that can change the strength of a force, its speed, or its direction and a machine reduces the amount of work to be done. A.) True B.) False C.) D.) E.)

  41. iRespond Question Multiple Choice F 4. The number of times a machine multiplies the effort force is the ____ of the machine. A.) Power B.) Force C.) Work D.) Mechanical advantage E.)

  42. 5. If a lever has a mechanical advantage of 10, can a 500 N rock be lifted with an effort force of 50 N? iRespond Question Multiple Choice F A.) Yes, it can be lifted B.) No, there is not enough force C.) Not enough information to determine the answer D.) E.)

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