SIMPLE MACHINES - LEVER

Name: SIMPLE MACHINES - LEVER
Uploaded: 2017-08-14T19:40:59+00:00
Duration: PTM12S18
Channel: Neal Carpenter
Description: SIMPLE MACHINES - LEVER

SIMPLE MACHINES - LEVER

A 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).

Anatomy of a lever

The 3 Classes of Levers The class of a lever is determined by the location of … - the effort force - the load and - the fulcrum.

The 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 middle

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

Anatomy of a first-class lever

First class lever Common examples of first-class levers include crowbars, scissors, pliers, tin snips and seesaws.

First class 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).

First-class lever Fulcrum is between EF (effort) and RF (load). Effort moves farther than Resistance. Multiplies EF and changes its direction.

First-class lever The 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.

Second-class lever In a second-class lever the load is located between the fulcrum and the effort force.

Anatomy of a second-class lever effort load fulcrum Resistance distance Effort distance

Second-class lever Common examples of second-class levers include nut crackers, wheel barrows, doors, and bottle openers.

Second-class 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.

Second-class lever The 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.

Second-class lever RF (load) is between fulcrum and EF Effort moves farther than Resistance. Multiplies EF, but does not change its direction.

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

Anatomy of a third-class lever effort load fulcrum Resistance distance Effort distance

Third class lever Examples of third-class levers include tweezers, hammers, and shovels.

Third-class 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.

Third-class lever The 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.

Third-class lever EF is between fulcrum and RF (load). Does not multiply force. Resistance moves farther than Effort. Multiplies the distance the effort force travels.

SIMPLE MACHINES – LEVER “FLE123”
First-class lever Second-class lever Third-class lever Fulcrum is between EF (effort) and RF (load). Effort moves farther than Resistance. Multiplies EF and changes its direction. EF is between fulcrum and RF (load). Resistance moves farther than Effort. Does not multiply EF. Multiplies the distance the effort force travels. RF (load) is between fulcrum and EF Effort moves farther than Resistance. Multiplies EF, but does not change its direction.

SIMPLE MACHINES – LEVER Trade-off
First-class lever Second-class lever Third-class lever 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. EF 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. RF (load) is between fulcrum and EF Requires more EF, but, load moves larger distance. Multiplies EF, but does not change its direction.

SIMPLE MACHINES “FLE123”

B C

What do you know ? Let’s find out!

What class of lever is this? 1st 2nd 3rd This page is set to work with Promethean ActivOffice and ActivExpressions.

Anatomy of a lever C. A. E. B. D. This page includes “self-paced questions” set to work with Promethean ActivOffice and ActivExpressions.

Anatomy of a lever A. B. D. C. E. This page includes “self-paced questions” set to work with Promethean ActivOffice and ActivExpressions.

Anatomy of a lever E. A. D. This page includes “self-paced questions” set to work with Promethean ActivOffice and ActivExpressions. B. C.

Which class of lever multiples force but only moves the load a short distance? 1st 2nd 3rd This page is set to work with Promethean ActivOffice and ActivExpressions.

Which class of lever moves the load the greatest distance but requires the greatest effort force? 1st 2nd 3rd This page is set to work with Promethean ActivOffice and ActivExpressions.

Which class of lever multiplies effort force and changes direction of force? 1st 2nd 3rd This page is set to work with Promethean ActivOffice and ActivExpressions.

Which class of lever multiplies effort force, but does not change its direction? 1st 2nd 3rd This page is set to work with Promethean ActivOffice and ActivExpressions.

Which class of lever does not multiply effort force but does multiplies the distance the effort force travels? 1st 2nd 3rd This page is set to work with Promethean ActivOffice and ActivExpressions.

SIMPLE MACHINES - LEVER

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