code for diagram

> para:=plot([5*t,-4.9*t^2+8.66*t+19.6,t=0..3.07],
thickness=3,xtickmarks=[5,10,15,20,25],
ytickmarks=[5,10,15,20],labels=[X,Y],
labelfont=[TIMES,BOLD,18], axesfont=[TIMES,BOLD,14],scaling=constrained):
plots[display](para,view=[-5..30,-5..30]);