Muscle Forces Involving Levers
Muscle Forces Involving Levers
In physics, a level (from French lever, “to raise”, c.f. a levant) is a rigid object that is used with an appropriate fulcrum or pivot point to multiply the mechanical force that can be applied to another object. This is also termed mechanical advantage, and is one example of the principle of moments. A lever is one of the six simple machines.
The three classes of levers
There are three classes of levers. First class lever, Second class lever, and Third class lever. They represent variations in the location of the fulcrum and the input and output forces.
First-class levers
A first-class lever is a lever in which the fulcrum is located in between the input force and the output force. In operation, a force is applied (by pulling or pushing) to a section of the bar, which caues the lever to swing about the fulcrum, overcoming the resistance force on the opposite side. The fulcrum is the center of the lever on which the bar (as in a seesaw) lays upon. This supports the effort arm and the load.
Second-class levers
In a second class lever the input is located to the far side of the bar, the output is located in the middle of the bar, and the fulcrum is located on the side of the bar opposite to the input.
Third-class levers
It is to be noted that for this class of levers, the input effort is higher than the output load, which is different from the first-class and second-class levers. However, also notice that the input effort moves through a shorter distance than the load. Thus it still has its uses in making certain tasks easier to do. Third class lever uses the effort in the centre while the output load is on one side… raising the load on the opposite end.
Information Courtesy of Wikipedia
