Simple Machines Pulley

PULLEY

A pulley has a grooved wheel and a rope.The groove
is present around the rim of the wheel. The groove
keeps the rope in its place.The object to be lifted is
tied to one end of the rope.Force is applied to the
other end by pulling it. When the rope is pulled
downwards,the load is lifted upwards.

FIXED PULLEY

In this type of pulley,the wheel is attached to a hook or
a wall and spins at one fixed place.A fixed pulley
changes the direction of the force. For example,you
can pull down in order to lift something up.It makes
lifting the objects convenient. However,it does not
reduce the effort required to lift objects. In a fixed
pulley, the effort should be equal to the load to be
lifted .

FIXED PULLEY

Movable pulley

In this type of pulley , the wheel moves
with the load as load is attached to the
pulley. It reduces the effort required to lift
the load. It is pulley used to lift heavy
engines and fit them into vehicles

MOVABLE PULLEY

SIMPLE MACHINES

THEORY- 2

INCLINED PLANE,SCREW, WEDGE,WHEEL AND

AXLE

INCLINED PLANE

An inclined plane is a slope,with no moving parts.It
helps to move the heavy objects from higher surface to
lower surface. inclined planes called ramps are
provided in hospitals to carry wheelchairs and
stretchers. Roads in hilly regions are inclined
planes,with gentle slope ,which makes it easier for
vehicles to move up. Cars are loaded on trucks using
inclined planes.

INCLINED PLANE

SCREW

A screw is an inclined plane that is wrapped spirally
around a cylinder.It is used to hold things together. It
has grooves cut into it. One end of the screw is pointed
while other end has a groove.The head of a screw has
a groove. A screwdriver is fixed into this groove and
rotated. Due to spiral grooves, the screw moves into
the wood easily. A screw holds the wood more firmly
than a nail.

SCREW

WEDGE

A wedge is made up of two inclined planes. One
end is thick and blunt, whereas the other end is
narrow and sharp. A wedge can be used to cut and
split the things. force is applied to the thick end of
the wedge to cut objects placed at its sharp end.
An axe, a nail, a razor and a knife are examples of
wedges.

WEDGE

WHEEL - AND- AXLE

A wheel and axle consists of a large wheel which is
connected to a small cylindrical rod called axle. They are at
centre, they move together. When the axle is turned, wheel
also moves. When the steering wheel of a car is turned, the
effort is multiplied by the axle and wheel move faster. the
locking system of a doorknob is also a wheel and axle.
When we turn the knob ( wheel) the axle turns inside and
open the lock.

WHEEL AND AXLE

SCREW, WEDGE, WHEEL AND AXLE

RECAP

INCLINED PLANE HELPS TO MOVE HEAVY OBJECTS FROM HIGHER TO
LOWER SURFACES. EXAMPLE- RAMP

SCREW-A SCREW IS AN INCLINED PLANE THAT IS WRAPPED SPIRALLY
AROUND A CYLINDER.

WEDGE- A WEDGE IS MADE UP OF TWO INCLINED PLANES.

WHEEL-AND-AXLE- IT CONSISTS OF A LARGE WHEEL WHICH IS
CONNECTED TO A SMALL CYLINDRICAL ROD CALLED AXLE.