The position of a particle moving in space is given by the vector-valued function

MATHEMATICS · Single correct · AP · Calculus BC · Parametric, Polar, and Vector-Valued Functions · Parametric, Polar, and Vector-Valued Functions

Problem

\mathbf r(t)

. Which expression gives the particle’s speed at time

t

? (a)

|\mathbf r(t)|

(b)

\displaystyle\frac{d}{dt}|\mathbf r(t)|

(c)

|\mathbf r'(t)|

(d)

|\mathbf r'(t)|^{2}