1. A space vehicle accelerates uniformly from 85 m/s at t=0s to 462 m/s at t=10s. What is avg acceleration? How far did the space vehicle move from t=2s to t=6s. 2. Got the avg accel easily enough w basic equation for accel. Problem is conceptual with the displacement portion of the question. 3. I got the correct answer by using x=xo + vit + 1/2at2 for t=2s and t=6s and then basically did Δx= x6s-x2s. BUT...I don't understand why I can't just use Δx=vit + 1/2at2 with t=4 because the time difference between 6s and 2s is 4s. Isn't the t in that equation essentially a Δt? Shouldn't putting 4 in there tell me the distance it will travel in 4 s? And why do I get a third different answer if I use: Δx=1/2(vi+vf)Δt? I seem to be confused about what Δx means and when t vs. Δt is used. Or something. Ugh. Sorry. Help!