Question

You can calculate acceleration with the following equation:
Acceleration = (final velocity - starting velocity) ÷ time it takes to change velocity

A plane passes over Centerville with a velocity of 9,000 m/s north. Fifty seconds later it passes over Middleton at a velocity of 12,000 m/s north. What is the plane's acceleration from Centerville to Middleton?
60 m/s/s north
40 m/s/s north
240 m/s/s north
120 m/s/s north