Simple Machines Classes of Levers

Simple Machines

Levers

How Do Levers Work?

SIMPLE MACHINES

a device that increases or changes the direction of a force

Levers

Levers are probably the most common simple machine.

The fulcrum is the point in which a lever rests (pivots);

The load is what you are trying to move;

Effort is the force you apply.

First Class Levers

The fulcrum is between the effort and the load.

Second Class Levers

The load is between the effort and the fulcrum.

Third Class Levers

The effort is between the fulcrum and the load.

Leavers and Loads

A lever might be able to...

decrease the effort required to move a load;

change the direction that a load moves;

increase the distance that load moves;

Increase the speed with which a load moves.

Multiple Choice

WHAT ARE THE 3 MAIN PARTS OF A LEVER?

• FOOT, EFFORT, REPORT
• FULCRUM, STRUCTURE, EFFORT
• FULCRUM, EFFORT, LOAD

Multiple Choice

Simple machines make the work we have to do easier, but it is still the same amount of work.

• TRUE
• FALSE

Multiple Choice

Which part is the 'load'?

• Arrow

• Yellow box

• Blue triangle

Multiple Choice

What is the moment acting on the seesaw?

• 1.6Nm
• 15Nm
• 16N
• 4Nm

Multiple Choice

At what distance should a 2N load placed from the pivot so that the see saw won't move?

• 0.2m

• 0.5m

• 0.45m

• 0.42m

Multiple Choice

A boy of weight 600N sits on the see-saw as shown at a distance of 1.5m from the pivot. What is the force F required at the other end to balance the see-saw?

• 450 N

• 350 N

• 4.5 N

• 200 N

​Phet - Balancing Act

​Demo Levers