What are examples of 1st, 2nd, and 3rd class levers?
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Solution
Definition
Levers are the most fundamental machines or tools used for performing tasks with minimal effort.
A lever multiplies an input force into a larger output force, resulting in leverage.
First class lever
In this type of lever, the fulcrum is in between the load and the effort. Its order is represented as load-fulcrum-effort.
When elevating your head to head a football, this type of lever is located in the neck as shown in the figure below. The effort is provided by the neck muscles, the fulcrum is the neck, and the load is the weight of the head.
Second class lever
In this, the fulcrum is at one end and the force applied (effort) is on the other end. The weight (load) is situated in the middle of these two. The order of this would be fulcrum-load-effort. The application of force at one end will result in some work done on the other end.
This sort of lever may be found around the ankle. When standing on the toe tip, the fulcrum is the foot, the load is the weight of the body, and the effort is the contraction of the muscle. This is shown in the figure given below.
Third class lever
In this type of lever, the fulcrum is at one end and the force is applied in the middle and the weight is on the other end. The order is represented as a -fulcrum-effort-load. In this case, we have to apply more energy to displace the weight to a longer distance.
The fulcrum of a biceps curl is the elbow joint, the effort is provided by the biceps contracting, and the resistance is provided by the weight of the forearm as shown in the figure given below.
