You are using a wrench and trying to loosen a rusty nut You are using a wrench and trying to loosen a rusty nut. Which of the arrangements shown is most effective in loosening the nut? Least effective in loosening the nut?

V = ωR Objects moving in a circle Linear speed = V S=Vt the distance moved per unit of time S=Vt Angular speed = ω the angle moved per unit of time R φ=ωt φ Period = T the time required for one revolution Frequency = f the number of revolutions per unit time

V = ωR ac = ω2R=V2/R Objects moving in a circle Linear speed = V S=Vt the distance moved per unit of time S=Vt Angular speed = ω the angle moved per unit of time R φ=ωt φ Angular acceleration = α α =Δω/Δt a = αR

A) B) C) D) E) None of these A ladybug is clinging to the rim of a spinning wheel starts spinning CCW and speeds up. At the moment shown, what is the approximate direction of the ladybug's acceleration? A) D) C) B) E) None of these

A) B) C) D) E) None of these A ladybug is clinging to the rim of a spinning wheel which is spinning fast CCW and is slowing down. At the moment shown, what is the approximate direction of the ladybug's acceleration? A) D) C) B) E) None of these

V = Rω F = ma = mΔv/ Δt F = mRΔω/Δt FR = mR2Δω/Δt F θ V torque V0=0 MOMENT OF INERTIA angular acceleration

FR = mR2Δω/Δt torque MOMENT OF INERTIA angular acceleration τ = I × α

A mass is hanging from the end of a horizontal bar which pivots about an axis through it center, but it being held stationary. The bar is released and begins to rotate. As the bar rotates from horizontal to vertical, the magnitude of the torque on the bar.. A: increases B: decreases C: remains constant

As the bar rotates from horizontal to vertical, the magnitude of the angular acceleration  of the bar.. A: increases B: decreases C: remains constant

A mass m hangs from string wrapped around a pulley of radius R A mass m hangs from string wrapped around a pulley of radius R. The pulley has a moment of inertia I and its pivot is frictionless. Because of gravity the mass falls and the pulley rotates. R m The magnitude of the torque on the pulley is.. A: greater than mgR B: less than mgR C: equal to mgR (Hint: Is the tension in the string = mg?)

τ = I × α I = m1R12+m2R22 V F R I = ∑ I θ m1 m2 V0=0

Moment of inertia is larger in situation: M, R, L Moment of inertia is larger in situation: A B C the same A B C

Moment of inertia is larger in situation: B the same

HW. Chapter 8.5 Quizzes and Examples!!! Problems 32, 33, 36, 40