Answer
a) $900m$
b)$60ms^{-1}$
Work Step by Step
a)Distance travelled by Tina is equal to distance travelled by David
$30 t = ut + \frac{1}{2}at^2$
$30 = 0 +\frac{1}{2} 2t$
$ t= 30s$
thus distance travelled by David is $30t = 900m$. Same distance is travelled by Tina when she passes David
b) Velocity when Tina passes David is
$ v= u + at$
$ v= 0 +2*30$
$v =60ms^{-1}$
