ClearAll;
$DefaultFont = {"Times-Roman",10};
Needs["Graphics`Graphics`"];
c1 = 0.29; c2 = 0.32; c3 = 0.34; s = (14 + Sqrt[31])/60;
v[t_]:= 350(10 t - 3)(20 t - 1)(7 - 20 t)/9;
plv = Plot[v[t],{t,0.28,0.35}];
vp[t_] = D[v[t],t];
plvp = Plot[vp[t],{t,0.28,0.35}];
xticks = {0.285,0.31,{s,"s"},0.335};
yticks = {-50,-25,0,25};
line1 = Graphics[{Dashing[{0.01,0.01}],Line[{{c1,0},{c1,v[c1]}}]}];
line2 = Graphics[{Dashing[{0.01,0.01}],Line[{{c2,0},{c2,v[c2]}}]}];
line3 = Graphics[{Dashing[{0.01,0.01}],Line[{{c3,0},{c3,v[c3]}}]}];
line4 = Graphics[{Dashing[{0.01,0.01}],Line[{{c1,0},{c1,vp[c1]}}]}];
line5 = Graphics[{Dashing[{0.01,0.01}],Line[{{c2,0},{c2,vp[c2]}}]}];
line6 = Graphics[{Dashing[{0.01,0.01}],Line[{{c3,0},{c3,vp[c3]}}]}];

upper = Show[plv, line1, line2, line3, AxesLabel->{None,"y"},
			AxesOrigin->{0.275,-1},Ticks->{xticks,yticks},
			PlotRange -> {{0.28,0.35},{-51,29}},
			PlotLabel->FontForm["(a) y = v(t) = V'(t)",{"Courier",10}]];
lower = Show[plvp, line4, line5, line6,
			AxesLabel->{None,"y"},Ticks->{xticks,Table[1000(i-3),{i,6}]},
			AxesOrigin->{0.275,-1},
			PlotRange -> {{0.28,0.35},Automatic},
			PlotLabel->FontForm["(b) y = v'(t) = V''(t)",{"Courier",10}]];
Show[GraphicsArray[{{upper},{lower}},PlotLabel->"Figure 14.3"]]