I quite honestly didn't even use that equation. I basically did what you said, dividing the total distance traveled by the total time.
avg vel = (40 *.5t + 10 *.5t)/t
= t(40*.5 + 10 * .5)/t
= (40 * .5 + 10 * .5)
= 25
ummm...?
Homework Statement
First half of a trip is @ 10 MPH
Second half of a trip is @ 40 MPH
Avg velocity?
Homework Equations
(Vi+Vf)/2 = avg velocity...?The Attempt at a Solution
K, this is obviously a simple question but for some reason when I do it I get it wrong, and I'm 100% sure I'm right. But...