Answer:
approximately 7 seconds
Explanation:
The given scenario is just an example of Projectile Motion.
In this question, we are given:
- Initial Velocity (u) = 40 m/s
- Angle of Elevation (θ) = 60 degrees
- Distance of Bird (s) = 145 meters     [Not used for the time of flight]
Time of Flight:
[tex]T = \frac{2uSin(\theta)}{g}[/tex]
we will use g = 9.8 m/s/s since we are not told otherwise.
[tex]T = \frac{2(40)Sin(60 degrees)}{9.8}[/tex]
[tex]T = \frac{40\sqrt{3}}{9.8}[/tex]
T = 4.081(√3) seconds
rounded to 7 seconds