how can a simple machine reduce force
TRANSCRIPT
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