Levers

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# Levers - PowerPoint PPT Presentation

Investigation 1:. Levers. Set the challenge…. Can you lift a heavy load with only one finger? Does it always take the same amount of force to lift a load?. Do you know that you can perform stunning feats of brute strength, far more amazing than the most powerful athletes?.

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## PowerPoint Slideshow about 'Levers' - signe-chaney

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Presentation Transcript
Investigation 1:

### Levers

Set the challenge…
• Can you lift a heavy load with only one finger?
• Does it always take the same amount of force to lift a load?
Do you know that you can perform stunning feats of brute strength, far more amazing than the most powerful athletes?
• It’s true, you can roll big boulders around like basketballs, lift half a dozen sixth graders off the floor with one hand, pull nails right out of wood, and flip the cap off a bottle of root beer with no difficulty at all.

What’s the secret?

LEVERAGE
• These tasks can be accomplished by using the aid of a lever!
• A lever is a simple machines that provides you with an advantage
• It can make work easier…

1. make a load easier to lift

2. reduce effort

3. Increase speed or distance

Parts of a Lever

There are 4 parts of a lever system:

• Fulcrum
• Effort
• Lever Arm

REMEMBER:

FELLA

How does it work?
• The lever arm is the straight, rigid bar
• The pivot point is the fulcrum
• A load is on one side on the lever
• Effort is applied to the other side to life the load
• Effort applied to one side of the lever lifts the load on the other side.
Can you find my FELLA?
• Draw & Label my parts on the note card provided
• Lever = a simple, rigid device that contains a fulcrum

1. Fulcrum = the pivot point or fixed point that the lever arm can rotate around

2. Effort =the force applied to move the load

3. Load = a mass lifted by the lever

4. Lever arm = the rigid bar or beam

How much force is needed to push or pull a load?
• It is measured in newtons
• Newtons = The newton, usually abbreviated as N, is the Standard International unit of force.
• Force is measured in newtons

Take a moment to learn about using spring scales!

Apply what you have learned…
• A mass of 1 kg pulls or pushes down (because of gravity) with a force of 10 N
• If a 5 kg cat is asleep on one end of a lever arm, you will have to push down on the other end of the lever arm with an effort equal to the force of _________ or the cat won’t budge.
• If

1 kg needs a force of 10 N

• Then,

5 kg needs a force of 50 N

To keep in mind while measuring…
• When you attach the scale to the lever with the rubber band, the mass of the scale itself, being pulled by gravity, exerts a force.
• However, you will see that the effort is 0 N
• In fact, the weight of the scale is pulling down with a force of 0.5 N
• Add on .5 N to the scale reading whenever you are pulling down with the scale!