Question

State the lever that always has a mechanical advantage less than 1.

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.

Third-class lever where the mechanical advantage is less than 1:

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.
4. The load and effort are in opposite direction.
5. The effort arm is always shorter than the load arm.
6. The mechanical advantage (MA) and velocity ratio (VR) are always less than 1.
7. It acts as a speed multiplier.
8. It always has a mechanical advantage of less than 1, because the load travels a greater distance than the force travels.
9. Consequently, the work requires more effort than would ordinarily be needed.

Examples of third-class lever:

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

Hence, the third-class lever always has a mechanical advantage less than 1.