Railways Basic Science and Engineering Simple Machine Levers and Simple Machines

Levers and Simple Machines

 LEVER

A lever is simply a plank or ridged beam that is free to rotate on a pivot. It is perfect for lifting or moving heavy things. It is a very usefull simple machine, and we can find them everywhere. Good examples of levers include the seesaw, crowbar, fishing-line, oars, wheelbarrows and the garden shovel.

Parts of a Lever

Levers have four very important parts - the bar or beam, the fulcrum die pivot or the turning point), effort (or force) and the load.

The beam is simply a long plank. It may be wood, metal or any durable material. The beam rests on a fulcrum (a point on the bar creating a pivot).

When we push down one end of a lever, we apply a force (input) to it. The lever pivots on the fulcrum, and produces an output (lift a load) by exerting an output force on the load. A lever makes work easier by both increasing input force and changing the direction of input force.

The Three Lever Classes

The parts of the lever are not always in the same arrangement. The load, fulcrum, and effort may be at different places on the plank.

Class One Lever

In this class, the Fulcrum is between the Effort and the Load. The mechanical advantage is more if the Load is closer to the fulcrum.

Examples of Class One Levers include seesaws, boat oars and crowbar

Class Two Lever

In this class, the Load is between the Effort and the Fulcrum. The mechanical advantage is more if the load is closer to the fulcrum.

Examples of Class Two Levers include wheelbarrows.

Class Three Lever

In this class, the Effort is between the Load and the Fulcrum. The mechanical advantage is more if the effort is closer to the load. An example of Class Three Lever is a garden shovel.

MACHINE

A machine is any device that does work. Machines make our lives easier because they reduce the amount of energy, power, and time we need to get one thing done by magnifying our input force.

Machines come in many sizes, shapes and forms. Some machines are very simple in its makeup and use whilst others are very complex. For example, a spade is a machine (a simple machine), and a space shuttle is a machine too (a complex machine),

Simple Machines

A simple machine is a tool, device or object with few moving parts that help us do work. Simple machines have been in use for a very long time. Early humans used simple machines to push, pull, lift, divide and crush things. They used simple machines to row rafts over water, build houses, split firewood, and carry heavy things from place to place. There are many simple machines are present in every place and all around us.

There are six types of simple machines - the inclined plane, the wedge, the screw, the lever, the wheel and axle, and the pulley. These six have very specific features and do unique jobs, even though some may work in similar ways. In fact, some simple ma- chines may be a combination of simple machines.

Important of Simple Machines

Simple machines, unlike complex ones, do not work on their own. They only increase the pull or push, (force or effort) that a person uses, increase or decrease the distance, or change the direction of a movement so that more work can be done. They can:

• transfer a force from one place to another
• change the direction of a force
• increase the magnitude of a force
• increase the distance or speed of a force

Features of a Simple Machine

• They do not use electricity
• They have one or fewer moving parts
• They give us mechanical advantage
• Even though they make work easier for us, they still need input (force or effort) from a person.
• They make tough jobs easier by changing the force, direction or speed of a movement

Complex Machines

Simple machines are different from complex (or compound machines). Complex machines, like trucks or wagons, or bicycles use many moving parts. They combine many simple machines such as levers, pulleys, and gears to get work done.