• A lever is a rigid rod arranged in such a manner that it can move freely around a fixed point.
• It consists of three parts.
Figure 44: A rod, fulcrum, load and effort make up lever
• This is the fixed point around which the rod moves.
• It is the object on which work is to be performed.
• A pulley is a wheel with a groove along its edge, for holding a rope or a chain.
Figure 58: A pulley
• Pulleys are usually used in sets designed to reduce the amount of force needed to lift a load.
• A small pulley at the top of a flagpole helps in raising the flag.Read More...
• An inclined plane is any slope or ramp.
• It makes it easier to lift a heavy object.
Figure 61: In ancient times, people and animals used to reach their destination by choosing steeper ramp
• We call it an "inclined plane" because it is a plane - a flat surface - and it is inclined - sloped, not level.Read More...
WHEEL AND AXLE
• This is a simple machine.
• It consists of a wheel rigidly attached to a rod (called axle). When one rotates the wheel, the axle also rotates.
Figure 64: A train has wheel and axle attached to it
• Wheels help people do work in two ways.Read More...
• A wedge consists of two inclined planes that meet at a sharp edge.
• Wedges are often used to cut or split objects.
• People have been using wedges in Africa since the earliest Stone Age, about 2.6 million years ago.
• These early wedges were stone hand-axes, and their sharp edges let people cut a hunk of meat off a gazelle to eat, or cut branches for firewood.Read More...