Why is centripetal acceleration negative in i direction and positive in j direction?

[haha1234]

Homework Statement

Homework Equations

The Attempt at a Solution

Why the centripetal acceleration is negative in i direction and positive in j direction?

 

[haruspex]

Why the centripetal acceleration is negative in i direction and positive in j direction?

From B, which way does the vector -i cos 35 + j sin 35 point?
What direction would you expect the centripetal acceleration to be in?

 

[BeBattey]

I recommend graphing the vector on your diagram, then graphing the vector alone. Plotting vectors always helps! Good luck.