Which of the following is an example of a second class lever?

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This question was previously asked in

RRB ALP Fitter 23 Jan 2019 Official Paper (Shift 2).

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Answer 1

Explanation:

Levers:

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.
Examples include wheelbarrows, staplers, bottle openers, nut crackers, and nail clippers.

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.

Lever 2dec1

Additional Information
Wheelbarrow:

A wheelbarrow is a small hand-propelled vehicle, usually with just one wheel, designed to be pushed and guided by a single person using two handles at the rear.
The wheelbarrow is designed to distribute the weight of its load between the wheel and the operator, so enabling the convenient carriage of heavier and bulkier loads than would be possible were the weight carried entirely by the operator.