Circular Motion & Angular Momentum Flashcards
Centre of Rotation Definition
Point at which particle rotates around. Centre of circle
Plane of Rotation Definition
2D plane containing circular path. Eg sheet of paper
Angular Velocity Vector Equation
- v = ω x r
Period Equation
P = 2π/ω
Axis of Rotation Definition
Line through the centre of rotation and normal to the plane of rotation
For a wheel, when it is rolling or slipping
- Rolling: Tangential Velocity = Linear motion (Static Friction)
- Slipping: Tangential Velocity ≠ Linear motion (Kinetic Friction)
- Equation: v_g = v - ωr
Centripetal Acceleration Equation
a = (ω^2)r
Torque (moment) equation
- τ = r x F
- r is the position vector at which the force F is acting on the particle
Angular Momentum Equation
L = r x p
“Momentum of momentum”
Torque - Angular Momentum Relation
τ = dL/dt
Torque is the rate of change of angular momentum
Moment of Inertia Equation
I = mr^2
Angular Momentum - Inertia Relation
L = Iω
Moment of Inertia for Rigid Bodies
- I = Σmr^2 = ∫ (r^2) dm
- Where r is the perpendicular distance from each element to the axis of rotation
Moment of Inertia for a hollow sphere
- I = (2/3)MR^2
- Axis of rotation through centre
Moment of Inertia for a uniform solid sphere
- I = (2/5)MR^2
- Axis of rotation through the centre