[Mentor's note: This thread was moved to the homework section from General Physics, so it doesn't use the template.] Going over a basic kinematics problem with the prompt stating vi=0, x=1000m and Δt=5 and vf and a need to be solved using average v and a. Calculated vf=200ms and a=40m/s/s. But then I also calculated for the same variables using x=.5(Δv)t and all turned wonky and I can't figure out why. Solving for vf=(2)(1000m)(1/5) I get 400m/s. Any insight into what error(s) Iam making?