It is the relative positions of these three points - the effort, the load and the fulcrum - that distinguishes the type or class of lever. There are three classes of lever 1st, 2nd and 3rd class. First class lever First class levers have the fulcrum between the force and the load.
In using a screwdriver to lift the lid from a paint tin you are moving the effort over a greater distance than the load. By having the fulcrum the rim of the tin close to the lid the load a larger force can be applied to the load to open the tin.
By this means you are reducing the effort required, this is what first class levers do best. Other examples of first class levers are pliers, scissors, a crow bar, a claw hammer, a see-saw and a weighing balance. In summary, in a first class lever the effort force moves over a large distance to move the load a smaller distance, and the fulcrum is between the effort force and the load.
As the ratio of effort force arm length to load arm length increases the mechanical advantage of a first class lever increases. Archimedes referred to a first class lever in his famous quote "Give me one firm spot on which to rest a fulcrum and I will move the Earth".
Second class lever In second class levers the load is between the effort force and the fulcrum. Second class lever - L oad is in the middle.
Third class lever - E ffort is in the middle. First, second and third class levers in the body Levers in our body are formed from bones, joints and muscles. A lever consists of: a rigid structure bone a force acting upon it muscle to produce a turning movement angular motion a fulcrum which is a fixed point joint a load or resistance that is placed on the rigid structure weight of body part being moved and anything that it is carrying A typical lever There are three types of lever.
First class lever This type of lever is found in the neck when raising your head to head a football. Second class lever This type of lever is found in the ankle area. Third class lever During a biceps curl, the fulcrum is the elbow joint, the effort comes from the biceps contracting and the resistance is the weight of the forearm and any weight that it may be holding. Mechanical advantages of levers When a lever's effort arm is longer than its load arm, it is said to have high mechanical advantage.
This lesson will answer those questions. Useful tool: Units Conversion. A Class 1 lever has the fulcrum placed between the effort and load. The movement of the load is in the opposite direction of the movement of the effort. This is the most common lever configuration. Note that the length of the effort arm can be greater than, equal to or less than the length of the load arm in a class 1 lever.
A Class 2 lever has the load between the effort and the fulcrum. In this type of lever, the movement of the load is in the same direction as that of the effort. Note that the length of the effort arm goes all the way to the fulcrum and is always greater than the length of the load arm in a class 2 lever.
A Class 3 lever has the effort between the load and the fulcrum. Both the effort and load are in the same direction. Note that the length of the load arm goes all the way to the fulcrum and is always greater than the length of the effort arm in a Class 3 lever.
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