Question

How are levers classified? Give two examples of each type.

Answer 1

Levers:

1. It is the simplest and most common machine used in everyday life.
2. A lever is a rigid, straight, or bent bar capable of rotating around a fixed point or its axis called the fulcrum.
3. A fulcrum (F) does not move but remains fixed when a lever is in use.

Principle of a lever and expression of mechanical advantage:

1. According to the principle of moments, in the equilibrium position of the lever,

$$\begin{gathered} Momentofloadaboutthefulcrum=Momentofeffortaboutthefulcrum \\ Load\times Loadarm=Effort\times Effortarm \\ \frac{Load}{Effort}=\frac{Effortarm}{Loadarm} \\ MechanicalAdvantage\left(MA\right)=\frac{Effortarm}{Loadarm} \end{gathered}$$

2. This expression is known as the law levers.

3. The MA of a lever is equal to the ratio of the length of its effort arm to the length of its load arm.

Classification of levers:

1. According to where the load and effort are located with respect to the fulcrum, there are three types or classes of lever: First-class lever, second-class lever, and third-class lever.

First-class lever:

1. This is a type of lever that has the fulcrum in between the weight and the force applied.
2. Its order is represented as force-fulcrum-weight.
3. This is the most basic type of lever.

Example of first-class lever:

1. Our hand pushing an object or seesaws, crowbars.
2. Using scissors represents the use of two first-class levers.
3. A wheel and axle is also an example.
4. Pulling a nail out of a wooden plank also represents a first-class lever.

Second class lever:

1. In this, the fulcrum is at one end and the force applied is on the other end.
2. The weight is situated in the middle of these two.
3. The order of this would be fulcrum-weight-force.
4. The application of force at one end will result in some work done on the other end.

Example of second class lever:

1. Wheelbarrow
2. Staplers
3. Doors or gates
4. Bottle openers
5. Nutcracker
6. Nail clippers

Third class lever:

1. These are the levers in which the fulcrum is at one end and the force is applied in the middle and the weight is on the other end.
2. The order is represented as a weight-force-fulcrum.
3. In this case, we have to apply more energy to displace the weight to a longer distance.

Example of third class lever:

1. Fishing rod
2. A broom
3. A baseball bat
4. A bow and arrow
5. Human jaw

Diagram of types of levers: