The main purpose of using a simple machine is to reduce the effort we put in to do any work. They have either few or no moving parts. We say work is done when an object moves in the direction of the force applied. Thus, a simple machine works by performing a few functions. It transfers force from one place to another. It increases the magnitude of the force applied. It changes the direction of the force applied. That is how we can lift or move heavy objects with the help of simple machines.
A lever is a simple machine that consists of a bar or a board resting on a support called a fulcrum. We can lift heavy objects easily with the help of a lever.
A pulley consists of a wheel that carries a rope around the rim of the wheel. We tie a heavy object to one end of the rope and pull it by applying force on the other end of the rope.
An inclined plane does not have a moving part. It consists of a flat surface inclined at an angle having one end higher than the other. We can move heavy objects from a higher level to the lower level and vice versa, by sliding them on the inclined plane.
A screw is also a type of inclined plane, where the inclined plane is wrapped around a cylinder. We use screws to hold things together.
A wedge consists of two inclined planes. We use a wedge to cut and split things. One end of it is thick and blunt, whereas the other end is thin and sharp.
Wheel-and-axel consists of a wheel, which is attached to a rod in the middle. This rod is called an axle. We use the wheel-and-axle to lift or move heavy objects.
The three main parts of a lever are load, effort, and fulcrum. The object that we move or lift is the load. We apply force in the form of push or pull. This is called effort. The fulcrum is the fixed point about which we move the rod. There are three types of levers based on the position of load, effort, and fulcrum.
1. Class I lever - The fulcrum is between the load and the effort. Example: hammer.
2. Class II lever - Load is between the fulcrum and the effort. Example: wheelbarrow.
3. Class III lever - Effort is between the fulcrum and the load. Example: tong.
The stairs are a type of inclined plane.
The scissors we use to cut paper or other objects is a simple machine.
The rolling pin, used to flatten the dough, is a simple machine.
The lid of a jar is a screw, which is a simple machine.
The wheelbarrow we use to carry around heavy objects is a combination of two simple machines, a lever, and a wheel and axle.
The coil wire may have to replaces if continuous usage is required.
