The bird is held in level flight due to the force exerted on it by the air as the bird beats its wings. what is the maximum value of this force due to the air? note that the bird's weight, the force of gravity acting on it, is calculated using w=mg, a result that will be justified in chapter 5.

 maximumforce is F = mg

Explanation:

For this case we must use Newton's second law,

     Σ F = m a

bold indicate vectors, so we will write it in its components x and y

 X axis

       Fₓ = maₓ

 Axis y

      Fy - W = m a

Now let's examine our case, with indicate that the bird is level, the force of the wings can have a measured angle with respect to the x axis, where the vertical component is responsible for the lift, let's use trigonometry to find the components

      Cos θ = Fₓ / F

      Fₓ = F cos θ

      sin θ = Fy / F

      Fy = F sin θ

Let's replace and calculate

      F sin θ -w = m a

As the bird indicates that leveling at the same height, so the vertical acceleration is zero (ay = 0)

       F sin θ = w = mg

The maximum value of this equation occurs when the sin=1, in this case

      F = mg

if you already have the answer to (a), then just work out how many periods there are in 1 minute, and that's the answer to (c).