simple machines friction review friction is the force we feel when things rub against each other the...
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Simple MachinesSimple Machines
Friction ReviewFriction Review
Friction is the Friction is the forceforce we feel when things we feel when things rubrub against each otheragainst each other
The The moremore things things are pushedare pushed together, the together, the moremore friction there is friction there is
It is the force that It is the force that opposesopposes motion. motion.
Friction ReviewFriction ReviewFriction Friction slowsslows down down the movement ofthe movement of things things
and turns motion into and turns motion into thermal energy thermal energy (heat).(heat).
When you When you rub your hands togetherrub your hands together you can you can feel the thermal energy produced.feel the thermal energy produced.
The mucus from The mucus from aa slugslug will will decreasedecrease friction friction as the slug slides along the ground.as the slug slides along the ground.
Simple MachinesSimple Machines
The purpose of a simple machine is to
A. increase the speed of work
B. change direction the force is acting in
C. increase Mechanical Advantage
- a machine’s ability to multiply input force
Inclined Inclined PlanePlane
A flat surface placed at an angle to a horizontal surface:
Examples:Examples:
Ramp, roadways, slide, Ramp, roadways, slide, stairsstairs
LeverLever
A lever is a rigid bar that rocks back and forth at the fulcrum
When a force is applied at one end, the other end moves.
The object to be moved is the load
Types of LeversTypes of LeversThere are three types of levers:
1st class lever- fulcrum is between the force and the load: crowbar, seesaw, pliers
2nd class lever – load is between the force and the fulcrum: nutcracker
3rd class lever – load and fulcrum are at either end: broom, baseball bat, hammer
WedgeWedge
A wedge is made of 2 inclined planes put together
A force is applied to the wedge to drive it into an object
Examples:knife, chisel, nail, axe
PulleyPulleyA pulley is a wheel with a grooved rim for
placement of a rope.
A downward force on one side
results in an upward movement
on the other side.
Examples:
flagpole, curtain cord, mini-blinds
Two Types Two Types of Pulleysof Pulleys
1. a fixed pulley –
attached to an object
2. a moveable pulley –
moves with the object
ScrewScrew
A screw is a spiral inclined plane.
Examples:
jar lid, machine screw, mountain road
Wheel and AxleWheel and Axle
A bunch ofA bunch of levers levers pivoting around one pivoting around one fulcrum.fulcrum.
A wheel or crank A wheel or crank
attached to an attached to an axleaxle. .
Examples:Examples:
door knob, wheels of vehicles, gearsdoor knob, wheels of vehicles, gears
Compound (Complex) MachinesCompound (Complex) Machines
A complex machine is made of two or more simple machines.
Examples:Bicycle, wheel barrow, Rube Goldberg machine
List the simple machines in the Rube Goldberg complex machine that are numbered.