LESSON – SIMPLE MACHINES
- Meaning and Parts of Lever
- Meaning and Types of Pulley
- Meaning and Advantages of Inclined Planes
A machine is a simple object which makes our work easier to do.
Many objects in the school and at home such as a pair of scissors, bottle opener and cutlass, are examples of simple machines.
In science, anything that makes us to use less energy to do much work or overcome a large force is called a machine.
Examples of simplest machines are the levers and pulleys.
MEANING OF LEVER
A lever is a simple machine that has the point of motion where effort can be made to carry a load.
EXAMPLES OF LEVER
The following are examples of lever,
5. Nut cracker
8. Hockey stick
9. Wheel barrow
10. Door handle
12. Hole puncher
PARTS OF LEVER
There are three parts of lever,
Fulcrum is the first class lever.
It is is at the middle of the effort and the load.
Load is known as second class lever.
It is in the middle between the fulcrum and the effort.
Effort is the third class lever.
It is at the middle, between the fulcrum and the load.
USES OF LEVER
The uses of lever are as:
1. Seesaw is used to have fun with a friend.
2. Scissor is used for cutting.
3. Crowbar used for split something apart or take out nails.
4. Hockey stick used to play hockey.
5. Wheel barrow is used move dirt or anything else.
6. Door handle is used to get through a door.
7. Dolly it is used to move heavy boxes and freight.
8. Hole puncher it is you for making hole on belt; etc
MEANING OF PULLEY MACHINE
A pulley is a wheel that has a smooth groove in its rim, with a rope passing through the groove. At times, there are loads that are too heavy to lift.
A pulley is a simple machine that is used to lift heavy objects.
A simple machine for overcoming this difficulty is the pulley.
EXAMPLES OF PULLEY MACHINES
The examples of pulley machines are as follows:
1. Flag pole
2. A sewing machine
3. Photocopy machine
4. Spring balance
5. A grinder machine
6. A modern elevator
7. A crane
TYPES OF PULLEY MACHINE
Basically, there are two (2) types of pulleys:
1. Single fixed pulley
2. Movable pulley
3. Compound pulley
1. SINGLE FIXED PULLEY
A fixed pulley’s wheel and axle stay in one place.
A good example of a fixed pulley is a flag pole.
When you pull down on the rope, the direction of force is redirected by the pulley, and you raise the flag pole.
2. MOVABLE PULLEY
A movable pulley is a pulley that is free to move up and down, and is attached to a ceiling or other object by two lengths of the same rope.
Examples of movable pulleys include construction cranes, modern elevators, and some types of weight lifting machines at the gym.
3. COMPOUND PULLEY
A compound pulley is a combination of fixed and movable pulleys. The third type of pulley is the compound pulley, which consists of combinations of fixed and movable pulleys.
The more complex the pulley, the more the effort needed to move the object decreases.
COMMON APPLICATIONS (USES) OF PULLEY
The common applications of pulley are as follows:
1. It is used for lifting heavy objects.
2. It is used in grinder and sowing machines.
3. It is used in an elevator.
4. It is used in raising a flag.
5. It is used for loading and off loading cargos.
6. It used for drawing curtains.
7. It is used ladder extensions.
8. It is used for climbing rock or mountain.
MEANING OF INCLINED PLANE
An inclined plane is a simple machine that allows one to use less force to move an object.
An inclined plane is a simple machine used to raise a load to places higher than the floor level.
EXAMPLES OF INCLINED PLANE
1. An axe
3. Automatic screwdriver
4. Screw jack
5. Office chair
6. Sliding board on children playground
ADVANTAGES OF INCLINED PLANE
The advantages of inclined plane are as follows:
1. An axe is used to slide wood.
2. Wedge is used to cut wood.
3. Automatic screwdriver is used to screw a nut.
4. Screw jack is used to lift up a car.
5. Office chair is used for balance and position.
6. Sliding board is used by children on playground.
7. Staircase is used to move from one floor to another.
8. Ladder is used to access a point on top.
Answer all the questions.
1. explain the meaning of lever.
2. name 5 common levers and machines in their homes.
3. locate the pivot (fulcrum) load and effort arms in common lever machines.
4. state 5 common uses of levers.
5. explain the meaning of pulley machine.
6. state 5 examples of simple Pulleys.
7. state 5 applications of pulley machines.
8. differentiate between fixed and movable pulleys.
9. construct and demonstrate the uses of pulley machines.
10. describe inclined plane.
11. mention 4 examples of inclined plane.
12. construct and use inclined plane to move objects.
13. state 5 advantages of inclined plane.