Explore topic-wise InterviewSolutions in .

1. inclined plane : A plane that is used to make a difficult task easy is called an inclined plane. Apart from this the ladders often found in use at homes and the inclined paths to climb on hills all are example of inclined planes.

2. Wheal and Axel : Wheel is a simple machine, wheel is one of the first inventions by humans. The wheel is often observed as an important part of complex machine.

1. inclined plane 

2. wheel and axle 

3. lever 

4. wedge 

5. screw

Lever is one of the simplest machines. It used to lift the heavy stone.

First order levers : In such type of lever the fulcrum (F) is situated somewhere in between the weight (W) and the effort (E).

Example : crowbar, a pliers.

Second order levers : In such a lever weight (W) is situated between fulcrum (F) and effort (E).

Example : nut cracker, fruit cutter.

Third order levers : The levers in which effort (E) is situated in between weight (W) and fulcrum (F) are called third order levers.

Example : A pair of tongs, holding weight in a hand.

1. Lever

2. Wedge

It is a simple tool which is used to join (fasten) two parts, it is called a screw. It is made of a cylindrical rod of metal by cutting spring like threads over it. It has a head which can be rotated to fasten it. Generally, in order to fasten a screw one needs to rotate it in clockwise direction where as to unfasten a screw we need to rotate it in anticlockwise direction.

The instruments or equipment’s which are used to do any work easily, quickly and properly are known as machines.

Simple machine is lever.

The equipment’s which are used to do any work easily, quickly and properly are known as machines. Machines can be divided in to two types simple machines and complex machines.

Lever of first order – crowbar, a pair of scissors, a comman balance, hand pump pincer, lever of second order – nutcracker, single wheeled barrow. Lever of third order pair of tongs to hold a weight in hand.

Write the name of some instruments or equipment’s in the following table that are used in order to make these tasks easier.

1. In house on street ramp

2. Slope on hill road

(b) frictional force

Axis on which wheel rotates, is called axle.

Wheel reduces the friction so there is no effort of labour.

In this there are two mutually inclined planes giving a sharp and common edge at front end and a broader and plane shape at back end. This type of figure in called as wedge shape,

By taking long length of distance between effort and fulcrum.

Weight × weight arm = effort × effort arm W × d = E × D

Fulcrum, effort, weight.

Second type.

1. rotate 

2. pulling 

3. handled 

4. direction

Principle of lever: In every balanced condition the product of weight and the weight arm is always equal to the product of effort and effort arm. This principle can be represented by weight x weight arm = effort x effort arm W x d = E x D The length of the effort arm is large which requires lesser effort for lifting a known weight. Because of this reason it becomes easier to lift or slide heavy object with the help of a crowbar. Therefore, we can say that with the help of a lever a greater force can be exerted at a point by applying a small force at some other point.

(b) they lessen frictional force

1. We have to exert a large force to roll attache without wheel and a little force to roll attache with wheel.

2. When we slide an attache case without wheels on the ground, the ground exerts a greater amount of frictional force on the attache case.

The machines which use electric motors, chains gears etc. besides simple instruments or equipment’s are called as complex machines. Examples are cycles motorcycles, sewing machine, huge factories, etc.

1. muscular force 

2. wheels 

3. Wheel 

4. second 

5. pulley

Screw is also a simple machine because it is used to tight two parts. Wedge is also used as simple machine. Its two mutually inclined planes gives a sharp and common edge at front end and a broader and plane shape at back end.

(c) weight, effort, fulcrum

(c) sewing machine

(c) work is done easily and efficiently