Flashback

• Calculate the angular speed of– the second hand on an analog clock– the minute hand on an analog clock– the hour hand on an analog clock• (ω = Δθ/Δt)

ωs = 0.105 rad/sωm = 0.0175 rad/sωh = 0.000145 rad/s

Symbols & UnitsQuiz on 2-3-2010

Circular MotionPhysics

Dave McCallister

Symbol for time

t

Unit for time

second (s)

Symbol for distance

d

Unit for distance

meter (m)

Symbol for speed

v

Unit for speed

meters per second(m/s)

Symbol for acceleration

a

Unit for acceleration

meters per second2

(m/s2)

Symbol for force

F

Unit for force

newtons (N)

Symbol for mass

m

Unit for mass

kilogram (kg)

Symbol for work

W

Symbol for kinetic energy

KE

Symbol for potential energy

PE

Unit for work & energy

joule (J)

Symbol for power

P

Unit for power

watt (W)

Symbol for angular displacement

Δθ

Unit for angular displacement

radians (rad)

Symbol for arc length

s

Unit for arc length

meters (m)

Symbol for distance from axis

(radius)

r

Unit for distance from axis

(radius)

meters

Symbol for angular speed

ω

Unit for angular speed

radians/second (rad/s)

Symbol for angular acceleration

α

Unit for angular acceleration

radians per second2

rad/s2

Symbol for tangential acceleration

aT

Units for tangential acceleration

meters per second2

(m/s2)

Symbol for centripetal acceleration

aC

Units for centripetal acceleration

meters per second2

(m/s2)

Symbol for centripetal force

FC

Unit for centripetal force

newtons (N)

Symbol for gravitational force

Fg

Unit for gravitational force

newtons (N)

Front matter

• The following slide shows what circular motion formulas will be given to you on Thursday’s circular motion quiz.

• Formulas:• θ(rad) = (π / 180°) x

θ(degrees)• Δθ = Δs/r• ωavg = Δθ/ Δt

• αavg = Δω/ Δt

• Δθ = ωI + ½ α t2

• ωF = ωI + α t

• ωF 2 = ωI 2+ 2α Δθ

• Δθ = ½ (ωF + ωI) t

• vT = rω

• aT = rα

• ac = vT2/r

• ac = rω

• Fc = mvt2/r

• Fc = mrω2

• Fg = G m1m2 / r2

• Constants:• G = 6.673x10-11 N m2/kg2