quiz 7, torque circular motion

where is the force applied that is most effective?

the farthest away from the rotation axis

effectiveness of force depends on

direction of force, magnitude of force, and location of force

what side of force causes rotation

the perpendicular side

torque SI unit

Nxm

net torque

proportional to acceleration

counterclockwise rotation

positive

clockwise rotation

negtive

net torque

sum of all the torques accounting for the proper signs

static equilibrium

net force is 0, 0 acceleration, no velocity

dynamic equilibrium

net force and acceleration 0, but velocity is constant

if an extended objects translational and rotational velocities are 0 and acelerations are 0

its in static equilirium

translational velocity

along a straight path

rotational velocity

around curved path

static equilibrium for toruqe

net force and net torque are 0

for an object to be in static equilibrium

it cant rotate about ANY point, net torque must be 0 at all points

when choosing a pivot point

chose what makes the calculations the easiest, where unknown forces act, or where multiple forces act

if we have a uniform symetrical object

the weight of the object is the center

there are systems where

net torque is 0 but not net force, or net force is 0 but not net torque, these are NOT in static equilibrium

if an object is tilted on one edge

it may or may not tip depending on how much its tipped.

bottom of object

base of support

if the center of gravity is within the base of support, the torque due to gravity will rotate it back down so the object is

stable

if the center of gravity is not within the base of support the torque will NOT rotate it back down

the object is unstable

critical angle formula

critical anlge= tan-1(t/2/h)

in UCM the velocity vector is alway

tangent to the path

in UCM the direction of the acceleration vector

is determined by the direction of the net force

acceleration vector componets

a parallel componet that changes magnitude, and a perpindicular componet that changes direction

acceleration parallel to velocity example\

only changes magnitude

acceleration perpindicular to velocity example

only direction changes

an object is in UCM if

it moves around a circle with a fixed radius at a constant speed v

direction of velocity

changes continuously

even though the speed might be constant the object is

accelerating since velocity vector always changes directions

since speed is constant

apar=0 and aperp=0

in UCM the direction of the acceleration vector always points

towards the center of the circle

in UCM where does the magnitude of acceleration point

depends on objects v and r

period

time it takes for one full revolution, T=time/revolution

frequency

number of revolutions per SECOND, f=revolutions/seconds

calculate speed with f

v=2pir/t= 2pirf

net force, centripital acceleration

vector sum of ALL forces, always points towards center of cirlce

relationship between frequency and period

T=rev/time, F=time/rev, T=1/f, F=1/t