Hi, Ok I have a bit of difficulty workin this Physics Mechanics problem. Ok here is the problem.... The coordinates of a plane flying in the xy-plane are given as functions of time by: X = 2.0m - at Y = bt^2 where a = 3.0 m/s and b = 2.5 m/s^2 A) Calculate the velocity vector as a function of time. B) Calculate the acceleration vector as a function of time. C) Calculate the magnitude and direction of the bird's velocity at t=2.9s. D) Calculate the magnitude and direction of the bird's acceleration a t=2.9s. Ok here's what i've accomplished so far... Code (Text): NOTE: /^ a(x) = a subscript x y| / | a(y) = a subscript y | / | i = unit vector component, x-axis | a / | j = unit vector component, y-axis | / |a(y)j | / | | /θ | bt^2 - *-------> | a(x)i | --------|--------------- 2.0 - at x Now I have these formulas. Code (Text): a = √((a(x))^2 + (a(y))^2) tan θ = a(y)/a(x) a(x) = a cos θ a(y) = a sin θ a = a(x)i + a(y)j Ok, now I believe you find a(x) and a(y) by taking the derivatives of bt^2 and 2.0 - at, thus getting 2bt and -a. But I don't quite understand what the question (part A) is asking, when they want the velocity vector as a function of time. I'm guessing its this: v(t) = -3.0i + 5.0tj if this is so then the acceleration vector (part B) is expressed as: a(t) = 5.0j So based on this i'm guessing part C is: v(2.9s) = 5.83 m/s but i'm not sure if this is correct either since part c asks for 'magnitude and direction', I feel like i'm missing something to my answer... Lastly following all the above part D should be: a(2.9s) ≈ 5.0 m/s^2 So....I hope I can get some insight in to this problem, I hope someone can help, and give me some guidance. Thanks.