An airplane starts at rest and accelerates down the runway for 20s. At he end of the runway, it's velocity is 80 m/a north. What is its acceleration?

a =v/t

a = 80/20 = 4 m/sec/sec north

20s 80 m/s

To find the acceleration of the airplane, we can use the equation of motion:

velocity = initial velocity + acceleration * time

In this case, the initial velocity is 0 m/s (since the airplane starts at rest), the final velocity is 80 m/s, and the time is 20 seconds.

Plugging these values into the equation, we have:

80 m/s = 0 m/s + acceleration * 20 s

To isolate the acceleration, we can rearrange the equation:

acceleration = (80 m/s - 0 m/s) / 20 s

Simplifying the expression:

acceleration = 80 m/s / 20 s

Finally, we calculate the acceleration:

acceleration = 4 m/s²

Therefore, the airplane's acceleration is 4 m/s² north.

20s 80 m/s