AP Calculus AB and BC glossary

Speed

Speed is the magnitude of velocity. Along a line that is the absolute value of the velocity function, and for a curve given parametrically it is the magnitude of the velocity vector, so speed is never negative in either case.

speed=∣v(t)∣\text{speed} = |v(t)|

For a particle moving along a curve described parametrically, speed is the magnitude of the velocity vector, (dxdt)2+(dydt)2\sqrt{\left(\frac{dx}{dt}\right)^2 + \left(\frac{dy}{dt}\right)^2}.

Physics defines speed as the magnitude of velocity, which is the reason it can never be negative: speed.

Appears in: Unit 4: Contextual Applications, Unit 8: Applications of Integration