FORCEDISTANCE WORK Work occurs when a force moves an object a distance. Work = force X distance (N-m) (N) (m)

Machines Help Out Machines “ multiply our effort ” and/or “change the direction of our effort”Machines “ multiply our effort ” and/or “change the direction of our effort” Machines make work easier but, the AMOUNT OF WORK DONE IS THE SAME !Machines make work easier but, the AMOUNT OF WORK DONE IS THE SAME !

Machines Help Out ! Machines give us a “mechanical advantage”Machines give us a “mechanical advantage” Mechanical Advantage (MA) - The number of times a machine multiplies your effortMechanical Advantage (MA) - The number of times a machine multiplies your effort

6 Simple Machines

SINGLE

SINGLE BLOCK AND TACKLE

EffortDistance ResistanceDistance Advantage Mechanical

LEVERS A lever is made up of 3 basic things 1.Effort 2.Resistance 3.Fulcrum (pivot point)

Levers have two arms. Effort Arm – the length of the lever from the fulcrum to the effort forceEffort Arm – the length of the lever from the fulcrum to the effort force Resistance Arm – the length of the lever from the fulcrum to the resistance forceResistance Arm – the length of the lever from the fulcrum to the resistance force

EffortArm ResistanceArm Advantage Mechanical EA LONGRA SHORT The trick for getting a large MA out of a lever is to make the EA LONG and make the RA SHORT.

There are 3 classes of levers. There are 3 classes of levers. How do you know which is which? 123FRE “what’s in between?”

ResistanceFORCE EffortFORCE Advantage Mechanical

INCLINED PLANES Three of the six machines are types of IP’s They have different tasks, but MA for each is found in the same way. Ramps WedgesScrews

EffortDistance ResistanceDistance Advantage Mechanical The longer the ramp, the greater the MA !

Wheel & Axle 1 turn of the pedal = 1 turn of the wheel The radius of the wheel is 4X longer around than the radius of the axle.

Big in front…small in back A Bicycle Built for SPEED

Small in front…Big in back A Bicycle Built for POWER

Newton’s First Law of Motion An object at rest wants to stay at restandan object in motion wants to stay in motion at a constant velocity until an unbalanced force acts on it. An object at rest wants to stay at rest and an object in motion wants to stay in motion at a constant velocity until an unbalanced force acts on it.

Newton’s Second Law of Motion An unbalanced force will cause a mass to accelerate. (speed up, slow down, change direction)

Newton’s Third Law of Motion action force reaction force Every action force has an equal and opposite reaction force Object A pushes on Object B Object B pushes back on Object A