Notes

Outline

Physics for PTA Unit 4 Torque, Simple Machines

What’s Torque ? Torque (t) the effectiveness of a force in causing rotation dependent on: the amount of force (F) the direction of force the point of application

Rotational Equilibrium S F = 0 no net force Fup = Fdown St = 0 no rotation tclockwise = tcounterclockwise

Doing Work Applying a force that causes motion the product of force and the distance the object is moved in the direction of the force

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"Actual Mechanical Advantage" Actual Mechanical Advantage

Levers  IMA = reffort/rresistance 1st class

Pulleys   IMA = no. of strings Single fixed pulley Single movable pulley

Inclined planes IMA = length / height

Rotational Motion motion in a curved path rotational distance degrees, revolutions, radians 2p radians = 1 revolution = 360 degrees rotational speed (w) rpm, rps, rad/s

Centripetal Force force needed to make an object follow a curved path constantly change the motion (direction) centripetal acceleration centripetal vs. centrifugal

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1st class

2nd class

3rd class