Final answer:
The plane's velocity is calculated by finding the change in velocity divided by the change in time.
Step-by-step explanation:
To calculate the plane's velocity, we need to find the change in velocity divided by the change in time. Since the plane is traveling in the same direction at different speeds, we can subtract the initial velocity from the final velocity to find the change in velocity. In this case, the change in velocity is 260 m/s - 240 m/s = 20 m/s.
The change in time is given as 40 seconds. So, the plane's velocity is 20 m/s divided by 40 seconds, which gives us 0.5 m/s. Since the velocity is in the North direction, the answer is 0.5 m/s North.