A car initially traveling eastward turns north by traveling in a circular path at uniform speed as in the figure below. The length of the arc ABC is 260 m, and the car completes the turn in 40.0 s.

I need to find the acceleration at a point 35 degrees below the horizontal in terms of vectors I and j

Can anyone point me in the right direction?!

The acceleration vector for an object moving along a circular arc at a uniform speed is directly towards the center of circle. Your problem makes reference to a figure, which you did not include, so I can't tell what you mean by "35 degrees below the horizontal." But if you draw a line fom that point to the center of radius for the turn you'll have your direction of acceleration. It's magnitude is v^2/r. You then need to resolve that vector into horizontal and vertical components to get the answer in terms of vectors I and j.