A small airplane starts from rest at one end of a runway and accelerates at 4.0 m/s^2 for 15 s before takeoff.

(a) What is the speed at takeoff? The answer was provided by the instructor as 60m/s.

I am using the acceleration equation (acceleration = change in velocity/time interval). The final velocity (4.0 m/s^2), starting velocity (rest which implies is 0), and time interval (15 s) are given in the answer.

1. Solve the change in velocity by subtracting the 4.0 m/s^2 - 0. The answer is 4.0 m/s^2.

2. Solve the acceleration equation (Acceleration = 4.0 m/s^2 / 15s)

so how does 4.0 m/s^2 / 15s = 60 m/s?

Guest May 26, 2017