#### Answer

a). $average \,velocity = \frac{final \,position - initial \,position}{time\, difference}$
So,
for AB, average velocity = $\frac{1-1}{1-0}=0\, m/s$
for BC, average velocity = $\frac{7-1}{3-1}=3\, m/s$
for CD, average velocity = $\frac{9-7}{4.5-3}=1.33\, m/s$
for DE, average velocity = $\frac{7-9}{6-4.5}=-1.33\, m/s$
for EF, average velocity = $\frac{2-7}{9-6}=-1.67\, m/s$
for FG, average velocity = $\frac{2-2}{11-9}=0\, m/s$
for BG, average velocity = $\frac{2-1}{11-1}=0.1\, m/s$
b). A motion is uniform only when rate of change of position is constant with time, which happens in AB and FG,
Rest BC,CD,DE,EF,FG are non-uniform.
c). Since the tangent at D has zero slope, the instantaneous velocity at D = 0.