Lever
A lever is a simple machine that can be used to multiply force by placing a small force at the far end of a rigid beam balanced over a fulcrum. A lever's beam can be made of any material, but it must be strong enough to be able to resist loads at the fulcrum point.
Levers are classified into three classes, based on the distance between the load, the fulcrum, and the location of the force applied.
First class
In first class levers, the fulcrum us located between the load and the applied force. The shorter the distance between the fulcrum and the load, the less force needs to be applied at the opposite end of the beam.
First class levers are best for lifting large loads with small applications of force.
Examples of first class levers include crowbars, car jacks, and teeter-totters.
Second class
In second class levers, the load is between the applied force and the fulcrum. If the load is closer to the fulcrum than it is to the applied force, then the force required to move the load is reduced. If the load is closer to the applied force than it is to the fulcrum, then the force required to move the load is increased..
Examples of second class levers include the the dolly, wheelbarrow, and bottle opener.
Third class
In third class levers, the applied force is between the load and fulcrum. Third class levers are best at moving loads large distances or with precision.
Example of third class levers include tongs, fishing rods, or a shovel.
Dependencies
- Simple Machines
- Lever