Circular motion

The radian
1. This is the SI unit for an angle
2. "A radian is the angle subtended by a circular are with a length equal to the radius of the circle"
  1. Degrees*(π/180)= Radians
Angular velocity
1. "The rate of change of angle for an object moving in a circular path"
  1. ω=θ/t
  2. ω=(2π)/T
  3. ω=2πf
2. ω
3. rad s^-1
Centripetal force
1. When moving in a circular path, the direction continuously changes
  1. Velocity constantly changes although speed remains the same
    1. Hence the object must be constantly accelerating
      1. This acceleration requires a resultant force (i.e centripetal force), this always acts towards the centre & perpendicular to the velocity
        The centripetal force has no component in the direction of motion
        Gravitational attraction (Satellite)
        Friction (Car)
        Tensions (String)
2. F=(mv^2)/r
3. F=m(ω^2)r
Linear velocity
1. The linear velocity is always at a tangent to the circular path
  1. v=(2πr)/T
  2. v=ωr
  3. For a given angular velocity, the linear velocity at any instance is directly proportional to the radius
Centripetal acceleration
1. The acceleration for an object travelling in a circular path at constant speed
2. a=-(ω^2)*r
3. This acts towards the centre of a circle

Resource summary

	Created by Connor O'Hare over 6 years ago