Page 234 - New Medley 5 Semester 2

Machines are of following two types:

 Simple machines: ere are three types of simple machines—lever, pulley

and inclined plane. Wheel and axle, wedge and screw are modi cations of
these three simple machines.

Inclined plane Crowbar Screw

Pulley
Scissors Knife Hammer
Some simple machines

 Complex machines: A complex machine is made up of two or more simple

machines. For example, washing machine and mixer-grinder.

Here, we will study about the simple machines only.

Lever

A lever is a rigid rod which can be turned about a

xed point. e xed point around which a lever can
be turned is called fulcrum. e weight which is to

be li ed is called load. e force applied on the lever

is called e ort. A man turning a rock with a rod

A lever helps to li or move an object with less e ort. If you have to move a
boulder, you use a lever. If you want to take out jam from a bottle, it is easier

to do so using a spoon rather than trying to do it with your ngers.

Activity S E L Self-Awareness • Hands-on Learning

Take a pair of scissors, forceps, pliers, bottle opener, and find out in them the points of the
fulcrum, the load and the effort.

Types of Lever
Depending on the position of fulcrum, load and e ort, levers are classi ed into

rst class levers, second class levers and third class levers.

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