Circular Motion Cheat Sheet
Circular motion is one of the easier subjects you’ll have to deal with in your exam. Learn this lot well and you’ll bump up your score in no time. Buster Tests also has two tests on this, Circular Motion 1 and Circular Motion 2. Based on the A2 AQA Physics B.
Formulae
You are given
- v = r ω
You need to remember
- F = (m v²) / r
- a = v² / r
- θ = s / r
- ω = θ / t
- ω = 2π / r = 2πf
- a = ω² r
- F = m ω² r
Key
- F = tension in string (N)
- m = mass of object (kg)
- r = length of string / radius (m)
- v = linear velocity of object (ms-1)
- a = centripetal force (ms-2)
- ω = angular speed (rad s-1)
- T = period of rotation (s)
- θ = angular displacement (rads)
Extra bits
To find the vertical component of a circular motion:
- Use v = r ω
- then use v sin θ
where θ is the angular displacement.