11.1.3

Rotational Motion

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Rotational Motion

Rotational motion is described in a very similar way to linear motion.

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Angular displacement

  • Angular displacement is the change in angle, θ, usually measured in radians.
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Angular velocity

  • Angular velocity is the rate of change of angle with time, usually measured in radians per second.
    • ω=ΔθΔt\omega = \frac{\Delta \theta}{\Delta t}
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Angular acceleration

  • Angular acceleration is the rate of change of angular velocity, measured in radians per second per second.
    • α=ΔωΔt\alpha = \frac{\Delta \omega}{\Delta t}

Angular acceleration

There is a set equations to find quantities under constant angular acceleration.

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Angular velocity

  • The equation for angular velocity is:
    • ω=ΔθΔt\omega = \frac{\Delta\theta}{{\Delta}t}
  • Angular velocity can also be expressed in terms of linear velocity:
    • ω=vr\omega = \frac{v}{r}
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Angular acceleration

  • Angular acceleration is the rate of change of angular velocity. The equation for angular acceleration is:
    • Angular acceleration = change in angular velocity ÷ change in time
    • α=ΔωΔt\alpha = \frac{\Delta\omega}{{\Delta}t}
  • Where α\alpha is the angular acceleration.
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Angular SUVAT equations

  • There are angular versions of SUVAT equations which have the form:
    • ω2=ω1+αt{\omega_2}={\omega_1}+{\alpha}t
    • θ=ω1t+αt22\theta = {\omega_1}t+\frac{{\alpha}t^2}{2}
    • θ=(ω1+ω2)2t\theta = \frac{({\omega_1}+{\omega_2})}{2}t
    • ω22=ω12+2αθ{\omega_2}^2= {\omega_1}^2 + 2\alpha\theta
  • Where θ\theta is the angular displacement.

Jump to other topics

1Measurements & Errors

2Particles & Radiation

3Waves

4Mechanics & Materials

5Electricity

6Further Mechanics & Thermal Physics (A2 only)

7Fields & Their Consequences (A2 only)

8Nuclear Physics (A2 only)

9Option: Astrophysics (A2 only)

10Option: Medical Physics (A2 only)

11Option: Engineering Physics (A2 only)

12Option: Turning Points in Physics (A2 only)

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