Slide 1

The Six Simple Machines are:

1. Lever 2. Wheel and Axle 3. Inclined Plane 4. Wedge 5. Pulley 6. Screw

Slide 2

A simple machine has few or no moving parts.

Simple machines make work easier

Slide 3

Force is Push or Pull Work = Force x distance W = Fd Unit of Work is the Joule or J Power = Work divided by Time P = W/t Unit of Power is a Watt or W

Slide 4

The wheel and axle are a simple machine

The axle is a rod that goes through the wheel which allows the wheel to turn

Gears are a form of wheels and axles

Wheels on your bike are wheels and axle

Slide 5

Pulleys are wheels and axles with a groove around the outside

A pulley needs a rope, chain or belt around the groove to make it do work

Flagpole uses a pulley to raise the Flag

Slide 6

An inclined plane is a flat surface that is higher on one end

Inclined planes make the work of moving things easier

Ramp is a type of inclined plane

Slide 7

• Less force is needed to move an object from one height to another using an inclined plane than is needed to lift the object.

• As the inclined plane becomes longer, the force needed to move the object becomes smaller.

Slide 8

• Imagine having to lift a box weighing 1,500 N to

the back of a truck that is 1 m off the ground.

• You would have to exert a force of 1,500 N, the weight of the box, over a distance of 1 m, which equals 1,500 J of work.

Remember: W = Fd

Work = 1,500N x 1meter = 1,500J

Slide 9

• Now suppose that instead you use a 5-m long ramp.

• The amount of work you need to do does not change.

• You still need to do 1,500 J of work. However, the distance over which you exert your force becomes 5 m.

Slide 10

• If you do 1,500 J of work by exerting a force over 5 m, the force you push with is only 300 N instead of 1,500N if you pushed on flat ground

• The Equation to use is:

(J)

(m)

F = 1,500 5 = 300NF = 1,500 5 = 300N

Slide 11

Two inclined planes joined back to back.

Wedges are used to split things.

Slide 12

• Your front teeth are wedge shaped

• The teeth of meat eaters, or carnivores, are more wedge shaped than the teeth of plant eaters, or herbivores

Slide 13

A screw is an inclined plane wrapped around a shaft or cylinder.

The inclined plane allows the screw to move itself when rotated.

A lever is any rigid rod or plank that pivots, or rotates, about a point.

The point about which the lever pivots is called a fulcrum.

Input Force – is the force being applied by YOU….

Output Force- is the force that the MACHINE does

Slide 14

Fulcrum

Slide 15

Input force: the distance from the

Fulcrum to:

F-effort – (YOU)

Output force: the distance from the

Fulcrum to:

F- load – (OBJECT)

Input force

Output force

F – effort/YOU

F-load/Object

Fulcrum

Are you confused yet? Remember this to help you:

1.Input force is the same as F- effort

Who is the input force or the F-effort?

2. Output force is the same as F- load = Simple Machine

What is the simple machine in this example?

The Golf club

The Golfer

Slide 16

In a first class lever the fulcrum is in the middle and the F- load and F-effort are on either side

Think of a see-saw

or Scissors

Slide 17

In a second class lever the fulcrum is on one end, with the

F-load in the middle and

F-effort is on other end

Think of a

wheelbarrow Fulcrum

F- load

F-effort

Slide 18

In a third class lever the fulcrum is again at the end, but the F- effort is in the middle and F-load

is on the other end

Think of a pair of tweezers

What is it? It is how much larger is the Output

Force compared to Input force

The higher the MA, the less force you need to use to get the job done

The amount of Work you do doesn’t change, ONLY the amount of Force you need to use to get the job done

Slide 19

Slide 20

Using the distance from Fulcrum to Input and Output Force

Mechanical Advantage = Input force (cm)

of lever Output force (cm)

MA = 1/5

MA = 5

Slide 21

Use the following MA Equation:Mechanical advantage = Output force or

Fout Input force or Fin MA = Fout FinCalculate this problem: To open a can of soup you apply a force

of 50N on the can opener. The can opener applies a force of 750N on the can of soup. What is the Mechanical Advantage of the can opener?

* MA = Fout = 750N = 15 Fin 50N

* 750 divided by 50 = 15

* The MA of the can opener is 15

* The higher the MA, the less work you need to

do…!!!!!!

Answer:

Slide 22

Efficiency is comparing the amount of work you do compared to the amount of work the machine does

When a machine is efficient, you don’t have to do as much work

Efficiency is measured in % Efficiency = Work out X 100% = Work in eff = Wout x 100% = Win

Problem:

You do 100J of work pulling a nail out with a hammer. If the hammer does 70J of work, what is the hammer’s efficiency?

Slide 23

Answer:

eff = Wout = 70J = 70% Win 100J

Divide 70 by 100 = .70 x 100 = 70%

Therefore, the hammer is 70% efficient

Slide 24

Simple Machines can be put together in different ways to make complex machines

The Ultimate Machine

Slide 25 Review Questions

Question Number 1Question Number 1

Name this Simple machine

Inclined PlaneOr Wheel and Axle

Slide 26 Question Number 2

Which type of lever is this?

A. First – Class

B. Second – Class

C. Third - Class

Third-class lever

Slide 27 Question Number 3 All 3 pictures are an example

of which Simple machine?

Lever

Slide 28 Question Number 4

Which simple machines do you see in this picture?Inclined PlaneWheel and Axle

Slide 29 Question Number 5 A can opener is an example

of First - Class Lever?

True or FalseTrue

In the First-class lever the Fulcrum is in middle

Effort

Load

Fulcrum

Slide 26

Fill-in-the-Blank

6. Force is ______ or _______

7. Work = ______ x _________

8. W = ____

9. Unit of _______is the Joule or J

10. Power = ______divided by

11. P = _____

12. Unit of Power is a___________

Slide 30

push pull

force distance

Fdwork

time work

W/t

Watt or W

Slide 31 Questions

13. What is the Mechanical Advantage or MA?

14. Write the MA equation:

It is how much larger is the Output Force compared to Input force

Mechanical Advantage = Output force or Fout Input force or Fin MA = Fout Fin

Slide 32 Questions15. Explain what is efficiency?

16. What is the efficiency equation?

BONUS QUESTION:

What is the ultimate Machine?

SIMPLE MACHINES VIRTUAL QUIZ – TAKE THE QUIZ

Efficiency is comparing the amount of work you do compared to the amount of work the machine does

Efficiency = Workout X 100 = ____% Workin

eff = Wout X 100 = Win

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