1. The problem statement, all variables and given/known data The position of a particle in meters moving along the x-axis is given by: x=21+22t-6t^2 Calculate the average velocity of the object in m/s during the time interval t=1s to t=3s. 2. Relevant equations x=21+22t-6t^2 t=3 ; t=1 v avg. = Xf - Xi/Tf - Ti = Δx/Δt don't know if this applies but: instantaneous velocity = dx/dt = -12t+22 3. The attempt at a solution Hello all. I am a returning student with a Major in Civil Engineering. At the age of 35, it is difficult to remember sometimes what the simple answers are. I know this may seem elementary to some of you but I believe I am over thinking this question. Please help. My question is which answer is correct for the question asked? I attempted this 2 different ways and can't decide if one of them is correct or if either of them are correct. substituting: x=21+22(3)-6(3)^2 x=33m x=21+22(1)-6(1)^2 x=37m then 33-37/3-1 = -2 m/s for velocity avg. speed = absolute value of velocity = 2 m/s or I took the derivative of the initial equation and then substituted to get: v=-12t+22 v=-12(3)+22=-14 v=-12(1)+22=10 then -14-10/3-1=-12m/s = 12m/s Any help would be great. Thank you.