what are the three classes of lever
Answers
Lever
It is a rigid body that is capable of rotating about a fixed axis known as fulcrum. When an effort is applied to one point of the lever it overcomes a much bigger load at some other point. In this way, in levers the turning effect or moment of a small force is used to overcome a large weight or resistance.
There are 3 types or classes of lever:
1) Levers of the First order
The levers in which the fulcrum is present in the middle of effort and load are said to be the levers of the first order.
Ex- balances, see saw, crowbar
2) Levers of the Second order
The levers in which the load is in between the fulcrum and effort are said to be the levers of the second order.
Ex- wheel barrow, nut crowbar, mango cutter
3) Levers of the Third order
The levers in which the effort is in between the fulcrum and load are said to be the levers of the third order.
Ex- forceps, ice tongs
Answer:-
There are three types or classes of levers, according to where the load and effort are located with respect to the fulcrum. Since humans usually provide energy to levers, "effort" and "load" are often used instead of input and output.
Justification:-
Each has its own uses and advantages :-
Class 1 lever
A Class 1 lever has the fulcrum placed between the effort and load. The movement of the load is in the opposite direction of the movement of the effort. This is the most common lever configuration.
The effort in a class 1 lever is in one direction, and the load moves in the opposite direction.
Note that the length of the effort arm can be greater than, equal to or less than the length of the load arm in a class 1 lever.
Class 2 lever
A Class 2 lever has the load between the effort and the fulcrum. In this type of lever, the movement of the load is in the same direction as that of the effort. Note that the length of the effort arm goes all the way to the fulcrum and is always greater than the length of the load arm in a class 2 lever.
The load in a class 2 lever moves in the same direction as the effort.
Examples of Class 2 levers include:
- Wheelbarrow
- Crowbar
- Nut cracker
- Wheelbarrow is Class 2 lever.
Class 3 lever
A Class 3 lever has the effort between the load and the fulcrum. Both the effort and load are in the same direction. Note that the length of the load arm goes all the way to the fulcrum and is always greater than the length of the effort arm in a Class 3 lever. Also, load in a Class 3 lever moves in the same direction as the effort.
Because of the location of the effort with respect to the fulcrum, often a bearing or other device is needed to hold the beam in place as it pivots. Otherwise, the effort will pull the arm off the fulcrum.