central force
, where r is the position vector of P and r = |r|.
Examples are the gravitational force F = −(GMm/r3)r, and the force F = −(k(r−l)/r)r due to an spring of unit natural length (see Hooke's law).
- index set
- indicator function
- indifference curve
- indirect isometry
- indirect proof
- indirect proportion
- indivisible by
- induce
- induction
- inequality
- inertia
- inertial frame of reference
- inertial mass
- inertia matrix
- inextensible string
- inf
- infeasible
- inference
- infimum
- infinite
- infinite product
- infinite sequence
- infinite series
- infinite set
- infinitesimal