two dimensional position?

Question

I'm given a statement such as the vector position of a particle varies in time according to the expression r = (8.60 i - 8.40t^2 j) m.
Somehow, i have to find expressions for the velocity and acceleration as functions of time. (Using t, i, and j as necessary.); and determine the particle's position and velocity at t = 3.00 s.

Unfortunately, I'm not even sure how to rearrange it (or what its wanting me to rearrange into a function a T)

Answer 1

You were requested to solve this problem with calculus. Please say so if you have not learned, but it is too bad if you have learned and forgot about it.
r(t) = 8.60 i - 8.40t^2 j
v(t) = dr/dt = -16.8t j
a(t) = dv/dt = -16.8 j
The problem is asking you for r(3.00), v(3.00) and a(3.00). Please perform the numerical calculation and get the answers.