Page 122 - Viva ICSE Science 5 : E-book

Some situations where pulleys are used are drawing water from a well, raising a fl ag on
a fl agpole and loading goods.

There are two main types of pulleys—fi xed pulley and movable

pulley. Let’s discuss them in detail.

In a fi xed pulley, the pulley is attached or fi xed to a point such
that it does not move. Fixed pulleys change the direction of the

force applied, but require large eff ort to move an object. Wells and
fl agpoles are examples of fi xed pulleys. A well has a
fi xed pulley

In movable pulleys, the pulley moves with the load. The

advantage of this pulley is that it reduces the eff ort used to
pull load. Examples of movable pulley are cranes, ropeways,
and block and tackle pulley in sailing boats.

Ropeways have
movable pulley

Wheel and axle

A wheel and axle arrangement is a simple machine in which
a large wheel rotates around the centre called axle. An axle

is usually a smaller wheel attached at the centre of a larger
wheel. The wheel and axle must move together to form a
simple machine. Eff ort applied to the wheel helps in turning

the axle and vice versa. This arrangement is used for lifting
and moving loads. Some common examples are tyres of cars Wheel and axle
or trucks, screwdriver, steering wheel and door knobs.

tyres of truck screwdriver steering wheel door knobs

Examples of wheel and axle arrangement

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