Physics

Problem

The position of an object moving along

x

-axis is given by

x = a + bt^2

, where

a = 8.5 \text{ m}

and

b = 2.5 \text{ ms}^{-2}

and

t

is measured in seconds. The average velocity of the object between

t = 2 \text{ s}

and

t = 4 \text{ s}

is ____

\text{ms}^{-1}