Answer
(a) The change in speed is 12.0 m/s
(b) $v = 33.0~m/s$
Work Step by Step
(a) We can use the information in the question to write the linear equation for the speed:
$v = (6.0~m/s^2)~t+3.0~m/s$
We can find the change in speed in the time interval between 4.0 seconds and 6.0 seconds:
$\frac{\Delta v}{\Delta t} = m$
$\Delta v = m~\Delta t$
$\Delta v = (6.0~m/s^2)(6.0~s-4.0~s)$
$\Delta v = 12.0~m/s$
The change in speed is 12.0 m/s
(b) We can find the speed when the elapsed time is 5.0 seconds:
$v = (6.0~m/s^2)~t+3.0~m/s$
$v = (6.0~m/s^2)(5.0~s)+3.0~m/s$
$v = 33.0~m/s$
