What is the average speed of an object that is moving at 5 m/s5ms at t=0t=0 and accelerates at a rate of a(t) =t-4a(t)=t4 on t in [4,5]t[4,5]?

1 Answer
May 11, 2016

v_a=17/6" " m/sva=176 ms

Explanation:

(d v)/(d t)=a(t)dvdt=a(t)

d v=a(t)*d tdv=a(t)dt

int d v=int a(t)* d tdv=a(t)dt

v=int (t-4)*d tv=(t4)dt

v=t^2/2-4t +C " "t=0 ;v=5 m/s" ; "c=5 m/sv=t224t+C t=0;v=5ms ; c=5ms

v=t^2/2-4t+5v=t224t+5

(d x)/(d t)=v(t)dxdt=v(t)

d x=v(t)*d tdx=v(t)dt

int d x=int _4^5 v(t)*d tdx=54v(t)dt

x=int_4^5 (t^2/2-4t+5)d tx=54(t224t+5)dt

x=|1/2*t^3/3-4*t^2/2+5*t|_4^5x=12t334t22+5t54

x=(1/2*5^3/3-2*5^2+5*5)-(1/2*4^3/3-2*4^2+5*4)x=(12533252+55)(12433242+54)

x=125/6-50+25)-(64/6-32+20)x=125650+25)(64632+20)

x=125/6-25-64/6+12=61/6-13x=125625646+12=61613

x=(61-78)/6x=61786

x=|-17/6|x=176

x=17/6 metersx=176meters

v_a=x/tva=xt

v_a=(17/6)/(5-4)va=17654

v_a=17/6" " m/sva=176 ms