Notes on Simple Machine | Grade 8 > Science > Simple Machine | KULLABS.COM

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We use different kinds of machines and tools in our daily life. Simple machines are those instruments in which effort is applied at a more convenient point in a more convenient direction. The work done on a machine is called input and the work done by the machine is called output. Input is the product of force and distance through which force is applied and output is the product of load and distance through which load is moved. A simple machine is a device, which makes our work easier by

1. increasing the force applied
2. changing the direction of force applied
3. transferring the force from one place to another
4. increasing the speed of a force

All machines work on the principle that when the effort is smaller than the load, it has to move a greater distance than the load in order to lift it up. There are six types of simple machines, they are:

1. Lever
2. Pulley
3. Wheel and axle
4. Inclined plane
5. Screw
6. Wedge

#### Principle of a simple machine

The principle of machine is Input work = Output work

Or, E x E. d = L x L. d

Where, E = Effort

E. d = Effort distance

• A simple machine is a device, which makes our work easier by

1. increasing the force applied
2. changing the direction of force applied
3. transferring the force from one place to another
4. increasing the speed of a force
• Types of simple machines are:

1. Lever
2. Pulley
3. Wheel and axle
4. Inclined plane
5. screw
6. Wedge
• The principal of machine is Input work = Output work

.

#### Click on the questions below to reveal the answers

A simple machine makes the work easier and faster by:

• Increasing the force applied
• Changing the direction of force applied
• Transferring the force from one place to another
• Increasing the speed of a force

A machine is a device when force is applied to it, it makes our work easier, changes the direction of force and enhance the speed of the work.

The two types of simple machines are lever and Pulley.

There are six types of simple machines, they are:

1. Lever
2. Pulley
3. Wheel and axle
4. Inclined plane
5. Screw
6. Wedge

The principal of machine is

Input work = Output work

Or, E x E. d = L x L. d

Where, E = Effort

E. d = Effort distance

\begin{align*}\\ \text {effort} (E) = 100\: N \\ \text {load arm} (Ld) =195\: cm\\ \text {Effort arm} (Ed) = 5\:cm \\ \text {load} (l) = ?\: N \\ \text {we know} \\ \text {accoding to the principle of simple machine} \\ \text {load} \times \text {load arm} &= \text {effort} \times \text {effort distance} \\ \text {or,} \: E\times 195 &= 100 \times 5 \\ \therefore &= \frac {100 \times 5}{195} \\ &= 2.56\: N\\ \end{align*}

Seesaw has the fulcrum F at the centre and thus forms the lever of first class. Let the boy st at a distance X metre from the centre.

\begin{align*} \text {effort} (E) = 50\: kg \\ \text {load arm} (Ld) =1\: m \\ \text {load } (l) = 20 \: kg \\ \text {Effort arm} (Ed) = X\:m \\ \text {we know} \\ \text {accoding to the principle of simple machine} \\ \text {load} \times \text {load arm} &= \text {effort} \times \text {effort distance} \\ \text {or,} \: 50\times 1 &= 20 \times X \\ \therefore X = \frac {50}{20} \\ &= 2.5 m \\ \end{align*}

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Wedge
Spring
Screw
Pulley

Beam balance
Screw
Wedge
Spring
• ### The principal of simple machine is ______.

E x L= E.d x L.d

E x E. d = L x L. d

E x L.d= L x E.d

• ### Which one of the statement is not true for simple machine?

Does not change the direction of force applied

Increases the speed of work

Transfers the force from one point to another

Increases the force applied

• ### Use of simple machine enables us to ______.

apply force in a suitable direction

multiply force and gain speed

apply force at a suitable point

• ### What are the different kinds of simple machine?

Pulley

All of the answers are correct.

Wheel and axle

Lever

## ASK ANY QUESTION ON Simple Machine

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##### simple machine

Characteristics of simple machine

##### biplop swornakar

Why machine have 100% efficiency whereas we say machine have 100% efficiency?

##### Ritika

Find effort if effort distance is 2cm load distance is 1.5m and laod is 200N