circular motion
Let er = i cos θ + j sin θ and eθ = −i sin θ + j cos θ, so that er and eθ are rotations of i and j by θ anticlockwise. Then the previous equations become
If the particle, of mass m, is acted on by a force F, where 
, then the equation of motion 
gives 
and 
. If the transverse component F2 of the force is zero, then 
constant and the particle has constant speed.
See also angular acceleration, angular velocity, radial and transverse components.
- positive angle
- positive correlation
- positive definite
- positive direction
- positively oriented
- positive semidefinite
- possible
- posterior distribution
- posterior probability
- postmultiplication
- post-optimal analysis
- postulate
- potential
- potential energy
- potential infinity
- power
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- power series
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- precision
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- predator–prey equations
- predicate