Page 147 - Active Science 5 Ebook and Activity

b. Lever of second class: In this lever, load lies between the fulcrum and the effort.
Wheel barrow, nut cracker and bottle opener are examples of lever of second class.

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E

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Nut Cracker Wheel Barrow
c. Lever of third class: In this lever, effort is applied in between fulcrum and load.
Forceps, forearms (hands), spade and knife are examples of third class.
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Knife Spade
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Inclined Plane
An inclined plane is a sloping surface which reduces

the effort required to lift a load. A ramp, generally
seen in hospitals, hotels, movie halls, airports and
schools is an example of an inclined plane. It is
convenient to move an object on an inclined plane.
For example, slide in a park, etc.

Wheel and Axle Slide Inclined plane

The wheel was invented much later than the other simple machines. Wheels help people
to work in two ways. Firstly, like lever or inclined plane. Secondly, they reduce friction, so
that the system is easier to move. The wheel becomes a simple machine when combined

with an axle. The wheels and axle arrangement helps us to turn something more easily
or move something across a surface more easily.

Screw Driver Paddle Wheel Door Knob Wheel Barrow

A screw driver is a wheel and axle with handle as the wheel. In a screw driver, the force
applied on the wheel (handle) is transferred to the axle (which drives the screw).

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