Question

A car drives toward the right over the top of a hill, as shown below.

An illustration of car at the top of a hill pointing right and looking at the side of the car. The is a vector up labeled Z, a vector down labeled X, a vector left labeled Y and a vector right labeled W.
Which arrow represents the centripetal acceleration?

W
X
Y
Z

Answer 1

X — the centripetal acceleration points toward the center of curvature, which at the top of a hill is downward (magnitude v^2/R).