Question

the position of the object moving along x axis is given by x=a+bt2​

Answer 1

Explanation:

Position is given as   x=a+bt2=8.5+2.5t2

Position at t=2 s,  x2=8.5+2.5(2)2=18.5 m

Position at t=4 s,   x1=8.5+2.5(4)2=48.5 m

Displacement  S=x2−x1=48.5−18.5=30 m

Time taken  t=4−2=2 s

Average velocity  Vavg=tS=230=15 m/s