A car, initially going eastward, rounds a 90 degree bend and ends up heading southward. If the speedometer reading remains constant, what is the direction of a car's average acceleration vector?
-So i know the speed remains constant.
average acceleration =( final velocity - initial velocity ) / elapsed time
The Attempt at a Solution
initial velocity = vi + 0j
final velocity = 0i + -vj
average acceleration = (-vi + -vj) / elapsed time
I don't think that the time matters here, because the ratio of vj/vi will remain the same, so:
direction of motion = inverse tangent of (-vj/-vi) = 45 degrees.
I feel like the answer should be -45 degrees. Also the back of the book says average acceleration = 5.12 m/s2 and that the angle should be 41 degrees south of west. How can they get an actual value for average acceleration? Any help would be greatly appreciated.