Question

An airplane starts from rest and accelerates on a runway at 5m/s^2 for 7 seconds. How far down the runway is the plane after 7 seconds?

Answer 1

The distance traveled by airplane

$$d=v_it+\frac{at^2}{2}=0\times 7+\frac{5\times 7^2}{2}=122.5\;\rm m$$