SIMPLE MACHINES

SIMPLE MACHINES - LEVER

12SIMPLE MACHINES - LEVERA lever is a rigid bar that rotates around a fixed point called the fulcrum.

The bar may be either straight or curved.

In use, a lever has both an effort (or applied) force and a load (resistant force).

3Anatomy of a lever

SIMPLE MACHINES - LEVER

4The 3 Classes of Levers

The class of a lever is determined by the location of - the effort force - the load and - the fulcrum. SIMPLE MACHINES - LEVER

5The 3 Classes of Levers

Use FLE123 as a way to remember the class of a lever. The letter represents the part in the middle of the lever and the number is the class of lever.

F1 1st class with Fulcrum in middle

L2 2nd class with Load in middle

E3 3rd class with Effort in middleSIMPLE MACHINES - LEVER

6First-class lever SIMPLE MACHINES - LEVER

In a first-class lever the fulcrum is located at some point between the effort and resistance forces.7Anatomy of a first-class lever

SIMPLE MACHINES - LEVER

8First class lever SIMPLE MACHINES - LEVER

Common examples of first-class levers include crowbars, scissors, pliers, tin snips and seesaws. 9First class lever SIMPLE MACHINES - LEVER First-class lever always changes the direction of force (I.e. a downward effort force on the lever results in an upward movement of the resistance force).

10First-class lever SIMPLE MACHINES - LEVER

Fulcrum is between EF (effort) and RF (load).

Effort moves farther than Resistance.

Multiplies EF and changes its direction. 11First-class lever SIMPLE MACHINES - LEVERThe closer the fulcrum is to the load, the easier it is to lift objects.

The longer the effort arm, the less effort force is needed to lift the object.12Second-class lever SIMPLE MACHINES - LEVERIn a second-class lever the load is located between the fulcrum and the effort force.

13Anatomy of a second-class lever

SIMPLE MACHINES - LEVEREffort distanceeffort loadfulcrumResistance distance14Second-class lever SIMPLE MACHINES - LEVER

Common examples of second-class levers include nut crackers, wheel barrows, doors, and bottle openers.15Second-class lever SIMPLE MACHINES - LEVER - A second-class lever does not change the direction of force. - When the fulcrum is located closer to the load than to the effort force, an increase in force (mechanical advantage) results.

16Second-class lever SIMPLE MACHINES - LEVERThe closer the fulcrum is to the load, the easier it is to lift objects.

The longer the effort arm, the less effort force is needed to lift the object.17Second-class lever SIMPLE MACHINES - LEVERRF (load) is between fulcrum and EF

Effort moves farther than Resistance.

Multiplies EF, but does not change its direction.

18Third-class lever SIMPLE MACHINES - LEVER

With a third-class lever, the effort force is applied between the fulcrum and the resistance force.19Anatomy of a third-class lever

SIMPLE MACHINES - LEVEREffort distanceeffortloadfulcrumResistance distance20Third class lever SIMPLE MACHINES - LEVER

Examples of third-class levers include tweezers, hammers, and shovels.21Third-class lever SIMPLE MACHINES - LEVER

A third-class lever does not change the direction of force.

A third-class lever always produce a gain in speed and distance and a corresponding decrease in force. 22Third-class lever SIMPLE MACHINES - LEVERThe closer the effort is to the load, the easier it is to lift objects.

The longer the effort arm, the less effort force is needed to lift the object.23Third-class lever SIMPLE MACHINES - LEVEREF is between fulcrum and RF (load).Does not multiply force. Resistance moves farther than Effort. Multiplies the distance the effort force travels.

SIMPLE MACHINES LEVERFLE123EF is between fulcrum and RF (load).

Resistance moves farther than Effort. Does not multiply EF. Multiplies the distance the effort force travels.

Third-class lever Second-class lever First-class lever

RF (load) is between fulcrum and EF

Effort moves farther than Resistance.

Multiplies EF, but does not change its direction.

Fulcrum is between EF (effort) and RF (load).

Effort moves farther than Resistance.

Multiplies EF and changes its direction. 24SIMPLE MACHINES LEVERTrade-offEF is between fulcrum and RF (load).

Requires most EF, but load moves greatest distance. Does not multiply EF. Multiplies the distance the effort force travels.

Third-class lever Second-class lever First-class lever

RF (load) is between fulcrum and EF

Requires more EF, but, load moves larger distance.

Multiplies EF, but does not change its direction.

Fulcrum is between EF (effort) and RF (load).

Requires less EF, but, load moves only a short distance.

Multiplies EF and changes direction of force.2526SIMPLE MACHINESFLE123

27SIMPLE MACHINES - LEVER

BCA28 SIMPLE MACHINES - LEVERWhat do you know ?

Lets find out!29 SIMPLE MACHINES - LEVERWhat class of lever is this?1st2nd 3rd

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3536 SIMPLE MACHINES - LEVERWhat class of lever is this?1st2nd 3rd

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3637 SIMPLE MACHINES - LEVERWhat class of lever is this?1st2nd 3rd

This page is set to work with Promethean ActivOffice and ActivExpressions.3738Anatomy of a lever

SIMPLE MACHINES - LEVER C. A. E.B.D.This page includes self-paced questions set to work with Promethean ActivOffice and ActivExpressions.

3839Anatomy of a lever

SIMPLE MACHINES - LEVER A. B. D.C.E.This page includes self-paced questions set to work with Promethean ActivOffice and ActivExpressions.

3940Anatomy of a lever

SIMPLE MACHINES - LEVER A. B. D.C.E.This page includes self-paced questions set to work with Promethean ActivOffice and ActivExpressions.

4041 SIMPLE MACHINES - LEVERWhich class of lever multiples force but only moves the load a short distance?

1st2nd 3rd

This page is set to work with Promethean ActivOffice and ActivExpressions.4142 SIMPLE MACHINES - LEVERWhich class of lever moves the load the greatest distance but requires the greatest effort force?

1st2nd 3rd

This page is set to work with Promethean ActivOffice and ActivExpressions.4243 SIMPLE MACHINES - LEVERWhich class of lever multiplies effort force and changes direction of force?

1st2nd 3rd

This page is set to work with Promethean ActivOffice and ActivExpressions.4344 SIMPLE MACHINES - LEVERWhich class of lever multiplies effort force, but does not change its direction?

1st2nd 3rd

This page is set to work with Promethean ActivOffice and ActivExpressions.4445 SIMPLE MACHINES - LEVERWhich class of lever does not multiply effort force but does multiplies the distance the effort force travels?

1st2nd 3rd

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