# The position of an object moving along a line is given by p(t) = t^2 - 2t +3. What is the speed of the object at t = 3 ?

Nov 11, 2017

$4 m {s}^{- 1}$

assuming SI units

#### Explanation:

speed $= \frac{\mathrm{dp}}{\mathrm{dt}} = p ' \left(t\right)$

$p \left(t\right) = {t}^{2} - 2 t + 3$

differentiate $w r t \text{ } t$

$p ' \left(t\right) = 2 t - 2$

$p ' \left(3\right) = 2 \times 3 - 2 = 6 - 2 = 4$