 |
Machine |
| |
From times immemorial, man has used machines to help him in his work. Today, we are dependent on machine for almost every task. When we think of machines we always tend to think of big and complicated units with many moving parts like wheels and rollers and gears and shafts. In Physics the term 'machine' has a specific meaning. |
|
Simple Machines |
| |
A bicycle is a machine which is used to gain speed. We gain speed by exerting additional force. When we try to ride a bicycle up a steep hill, we soon realize that we gain speed by applying greater force. It is impossible to multiply both the force and gain the speed at the same time. |
|
Levers |
| |
A simple crowbar can be used to lift a heavy rock with a small effort. The crowbar is an example of a lever. |
|
Levers of the 1st Order [Class I Levers] |
| |
In this type of lever the effort and the resistance (load) are situated on either side of the fulcrum. |
|
Levers of the 2nd Order [Class II Levers] |
| |
In these type of levers the load is situated between fulcrum and effort. |
|
Levers of the 3rd Order [Class III Levers] |
| |
In class III levers effort is situated between the load and the fulcrum. |
|
Pulleys |
| |
Pulleys are used in everyday life. They are used in factories for lifting loads, in hoisting flags, in drawing curtains in theatres, in lifts, in drawing water from well etc. |
|
The Inclined Plane |
| |
A heavy load may be raised more easily by pulling it up along a sloping surface than by lifting it vertically. For example, heavy barrels are often loaded into vans by passing two ropes round them and hauling them up an incline formed by two stout planks held apart by iron rods. |
|
Gears |
| |
Gears are like a continuously rotating lever. By using different sizes of wheels, and different numbers of teeth, you can use gears as force multipliers or as distance multipliers. |
|
Wheel and Axle |
| |
At one end of the axle, a wheel of a greater diameter is fixed. The axle and the wheel both rotate about the same axis. Ropes have been wound around both the wheel and the axle. |
|
Summary |
| |
Machine is a device that is used to multiply force, or to gain speed, or to change the direction of a force, or transform energy. |
