What is the average speed of an object that is moving at 15 m/s15ms at t=0t=0 and accelerates at a rate of a(t) =7-2t^2a(t)=72t2 on t in [0,3]t[0,3]?

1 Answer
Mar 6, 2016

v_a=81/3=27" " m/sva=813=27 ms

Explanation:

v(t)=int(a(t)d tv(t)=(a(t)dt
v(t)=int (7-2t^2)d t" "v(t)=7x-2/3t^3+Cv(t)=(72t2)dt v(t)=7x23t3+C
if t=0" "v=15 m/s" "v(t)=7x-2/3t^3+15
Delta x=int_0^3 v(t) d t" "Delta x=int_0^3(7x-2/3t^3+15)d t
Delta x=|7/2x^2-2/12t^4+15t|_0^3
Delta x=7/2*3^2-2/12*3^4+15*3
Delta x=63/2-81/6+45" "Delta x=63/2-27/2+45
Delta x=36+45" "Delta x=81
v_a=81/3=27" " m/s