how can a simple machine reduce force

HOW CAN A SIMPLE

MACHINE REDUCE

FORCE?

WHAT IS A MACHINE?

Something that makes work easier to do

Example: It's easier to lift & carry a rock with a wheelbarrow that to

carry it with your hands

- They are machines with few or no moving parts

WHAT IS A SIMPLE MACHINE?

- It is a straight bar that moves on a fixed point "Fulcrum”

Examples: Seesaw

(1) Lever

Load

Fulcrum

Load

Fulcrum

-Pressing down on a lever, lifts up the load.-Levers change how much force you need to move something.

LEVERSWhat does the lever do?

-It makes it easier to lift loads.

What happens to the force?

-The force becomes less. -And the direction of force

changes to the opposite.

(2) Pulley

- It is a kind of lever that uses a wheel & a rope to lift an object

Examples:When you pull down one end of the rope,

the other end rises up

Wheel

Rope

PULLEYSWhat does the pulley do?

-It makes it easier to lift loads.

What happens to the force?

-The force becomes less. -And the direction of force

changes to the opposite.

(3) Wheel & Axle

- It is a kind of lever that uses a wheel that moves around an axle.

Examples: A Ferris wheel

Wheel

Axle

WHEEL & AXLEWhat does the wheel and axle do?

-It makes it easier to move loads.

What happens to the force?

-The force becomes less.

A Door knob

A Wheel barrow

A shopping cart

A Mouse wheel

It is a simple machine with flat & inclined surface which reduce the force needed to move an object.

Example: A Ramp- It is easier to slide a heavy box on an

inclined Plane than to lift it up.

(4) Inclined plane

INCLINED PLANEWhat does the inclined plane do?

-It makes it easier to carry loads up.

What happens to the force? -The force becomes less.

-And the distance becomes more.

- It is an inclined plane wrapped onto a spiral.

- "A screw changes a turning force into a downward force“ as we turn the screw, it moves down.

Example:{It is easier to turn a screw than to pound a

nail}

(5) A screw

SCREWWhat does the screw do?

-It makes it easier to fix loads.

What happens to the force?

-The force becomes less. -And the direction of force

changes from turning to downwards.

An Auger is a giant screw

It is a simple machine that splits objects apart.

"A Wedge changes a downwards force into sideways force"

Examples: The Head of an Ax The

Knife

(6) A Wedge

WEDGEWhat does the wedge do?

-It makes it easier to cut loads.

What happens to the force?

-The force becomes less. -And the direction of force

changes from downwards to sideways.

They are made of two or more simple machines

together.

Compound machines

EXAMPLES

2 wedges

Fulcrum “fixed point”

2 levers

A pair of scissors is a compound

machine that is made of two

wedges & two levers

Pulley Wheel & axle

A bicycle is a compound machine

that is made of pulleys & wheel &

axle.

Wheel & axle Fulcrum

Load

A Wheelbarrow is a compound machine

that is made of a lever & wheel & axle