Answer:
a) 15 m/s.
Step-by-step explanation:
s(t) = 2t^2+ 3t
Distance at 2 seconds = s(2) = 2(2)^2 + 3(2) = 14 m.
Distance at 4 seconds = s(4) = 2(4)^2 + 3(4) = 44 m.
Average velocity = distance travelled from t = 2 until t = 4 / time
= (44 - 14) / 4 -2
= 30/2
= 15 m / s.