# What is the average speed, on t in [0,5], of an object that is moving at 12 m/s at t=0 and accelerates at a rate of a(t) =5-2t on t in [0,4]?

$s = s + v t + \frac{1}{2} a {t}^{2}$
$s p e e d = \frac{\mathrm{di} s \tan c e}{t i m e}$