# Get the Knowledge that sets you free...Science and Math for K8 to K12 students

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## Simple Machines

The most advanced eco–friendly simple machines Unlike most electric bikes, which recharge as you pelt down hills or use the brakes, these bikes when kept in eco-charge mode, will power up even when you're pedaling on level ground, which helps you on heavy uphill treks. Another kind of electric bikes are the ones that come with gear technology and the drive system that can automatically optimize the power input of the motor relative to the rider whenever the sensors registers an additional torque required by the rider. Lets learn more of such simple machines which makes our life easier.

## After completing the topic, the student will be able to:

• Discuss different types and the uses of simple machines in daily life.
• Understand and employ the facts about the working of simple machines in day-to-day life.
• Identify different types of simple machines based on their usage.
• Explore different types of pulleys and investigate their importance in daily life science scenarios.
• Explore the forces that act on the body when it is lifted by a pulley and apply them to solve daily life science scenarios. Operate these pulleys, in various contexts to do a particular job smoothly.
• Distinguish and investigate about the different types of energy and their relevance in real world applications.
Claw hammer: Hammer pulling nail Claw hammer is used as a lever to pull a nail from a wood board. When the handle is pulled with a certain force (shorter arrow), the claw pulls the nail with a greater force (longer arrow). Here the ratio of the two forces is about 3.5.
Simple machines

When we do any work, force has to be applied. A force has to be used efficiently so that maximum work is done. For example, if a large load has to be lifted, then a large force has to be applied. Such a large force may not be available. Then how will you lift a large load? It is here where simple machines come into the picture. It is possible to magnify applied force with the use of simple machines. Simple machines perform work in such a way that the force applied is used efficiently and usefully.

Simple machine is a device through which an applied force at a point is transmitted to another point with a convenient change of magnitude and if required direction also. Without any conscious thoughts, we are always employing simple machines to make our lives better. Don't we use a fork to lift food from our plate, a pair of scissors to cut a cloth or a hinge to open a door? These are nothing but simple machines. Early man also employed some simple machines: used stone axe to cut or a long stick to shift a boulder. Archimedes is credited with the invention of the screw and the lever. Archimedes lived in Greece around the 250 B.C. He even pronounced, "Give me a place to stand and a long stick, I will lift the earth."

It is interesting to note that many of the parts of human or animal bodies function on the principle of levers. Jaws and elbows represent simple machines, too.
Thus a machine is a tool used to make work easier. Simple machines are simple tools used to make work easier. Compound machines have two or more simple machines working together to make work easier.

Inclined plane A wooden block accelerates down along an inclined plane, a type of a simple machine. The sum of the forces acting on the block (normal force, friction force and gravity force) is not zero.

Pushing, pulling, and lifting are common forms of work.

A villager does work when he pulls water from a well. Furniture movers do work when they move boxes. Gardeners do work when they pull weeds. Children do work when they go up and down on a see–saw. Machines make their work easier. The furniture movers use a ramp to slide boxes into a truck. The gardeners use a hand shovel to help pull the weeds. The children use a see–saw to go up and down. The ramp, the shovel, and the see–saw are simple machines.

Simple machines are meant for doing the following:

• To multiply force: A long stick can be used to lift or shift heavy loads.
• Apply force at a convenient point: Scissors is used to cut say cloth or paper. The force applied is on the scissors arms, away from the place where cutting needs to be done. Fire tongs are used for lifting burning pieces of coal. The force applied on the tongs is not at the place where it is exactly needed.
• Apply force in a convenient direction: When a person wants to pull water from a well, he stands on the side of the well, but the water bucket has to be lifted vertically upwards. A simple pulley is used to achieve this job.
• Lift heavy loads: A screw jack helps a person lift a heavy car. A simple shovel can lift heavy stones.
• Increase speed: A wheel in a cycle is used for increasing speed. A wheel on a grinding machine helps in executing the task at a faster speed.