Class 1 lever

With third class levers the effort is between the load and the fulcrum, for example in barbecue tongs. Other examples of third class levers are a broom, a fishing rod and a woomera.

A lever that has its point of resistance (load) between its fulcrum (point of support or axis of rotation) and point of effort (force application). In the human body, a second class lever is used when a person stands on tip-toe.

Well, a first-class lever is a stick where the fulcrum is in between the weight and the energy or force moving the weight (your hands, for example). There’s something pushing or pulling on one side, something pushing or pulling on the other side, and a fixed point in the middle.

A class 3 lever has the effort in the middle, the fulcrum at one end and the load at the other. An example of a class 3 lever is a broom. A broom is a third-class lever. Tweezers and tongs are pairs of third-class levers with the same fulcrum.

The advantage of a third-class lever is that the output force is applied over a greater distance than the input force. The output end of the lever must move faster than the input end in order to cover the greater distance.

There are three types or classes of levers, according to where the load and effort are located with respect to the fulcrum. Class 1 has the fulcrum placed between the effort and load, Class 2 has the load in-between the effort and the fulcrum, and Class 3 has the effort between the load and the fulcrum.

Third Class Levers In a third class lever, the effort is located between the load and the fulcrum. If the fulcrum is closer to the load, then less effort is needed to move the load. If the fulcrum is closer to the effort, then the load will move a greater distance. These levers are useful for making precise movements.

The biceps attach between the fulcrum (the elbow joint) and the load, meaning a biceps curl uses a third class lever.

Third-class levers are plentiful in human anatomy. One of the most commonly used examples is found in the arm. The elbow (fulcrum) and the biceps brachii (effort) work together to move loads held with the hand, with the forearm acting as the beam. The forearm remains static, and the load does not move (Figure 2A).

There are many examples of third class lever systems, including both flexion and extension at the knee joint. During flexion at the knee, the point of insertion of the hamstrings on the tibia is the effort, the knee joint is the fulcrum and the weight of the leg is the load.

A lever is a rigid object used to make it easier to move a large load a short distance or a small load a large distance. For example, the forearm is a 3rd class lever because the biceps pulls on the forearm between the joint (fulcrum) and the ball (load).

The joint is the fulcrum. The muscle contraction pulling on its insertion point is the effort.

An example of a first class lever in the human body is the head and neck during neck extension. The fulcrum (atlanto-occipital joint) is in between the load (front of the skull) and the effort (neck extensor muscles). The muscles are attached to the posterior part of the skull to allow for the greatest effort arm.

Levers can be used so that a small force can move a much bigger force. This is called mechanical advantage. In our bodies bones act as lever arms, joints act as pivots, and muscles provide the effort forces to move loads.

One of the most commonly used examples of first-class levers in human anatomy is the skull as it sits atop the first vertebra (the atlas). This unique joint allows the skull to nod forward and backward and side to side, acting as a first-class lever where the neck musculature provides the opposing forces.

A lever works by reducing the amount of force needed to move an object or lift a load. You will see that levers neither increase nor decrease the amount of total effort necessary. Instead, they make the work easier by spreading out the effort over a longer distance.

They allow a larger force to act upon the load than is supplied by the effort, so it is easier to move large or heavy objects. The longer the lever, and the further the effort acts from the pivot, the greater the force on the load will be.