Question

A particle moves according to the equation $x=t^2+3t+4$, the average velocity in the first $5s$ is

• A. $8m{s}^{-1}$
• B. $7.6m{s}^{-1}$
• C. $6.4m{s}^{-1}$
• D. $5.8m{s}^{-1}$

Answer 1

Answer: (A)

$8m{s}^{-1}$

$x=t^2+3t+4$
$v=\frac{dx}{dt}=2t+3$
$v_{avg}=\Sigma \frac{v_i}{6}=\frac{(2\times 15)+(6\times 3)}{6}=8m/s$