Use the definition: velocity (v = frac{Delta x}{Delta t})
Compute displacement: (Delta x = x_f – x_i)
Compute time interval: (Delta t = t_f – t_i)
Use consistent units (e.g., meters and seconds) so (v) is in m/s
For average velocity: (v_{text{avg}} = frac{x_f – x_i}{t_f – t_i})
For constant velocity: (v = frac{d}{t})
For velocity from a graph (position vs time): slope (v = frac{dy}{dx}) (tangent slope for instantaneous)
For velocity from a graph (velocity vs time): displacement (Delta x = int v,dt)
For instantaneous velocity (if position is (x(t))): (v(t) = frac{dx}{dt})
If given acceleration (a(t)): (v(t) = v_0 + int a(t),dt)
If given constant acceleration: (v = v_0 + at)
If using vectors: (vec{v} = frac{Delta vec{r}}{Delta t})
If speed and direction are needed: (vec{v} = text{speed}times) (unit direction vector)