Answer:
Option 3 = Downward and Backward
Step-by-step explanation:
While moving in a circle, the bird will experience following forces:
- Inward force (Centripetal Force)
- Outward force (Centrifugal Force)
- Backward force (due to air resistance)
- Downward force (due to Gravitational Force)
The first two forces are due to circular motion and these are equal in magnitude (mv^2/r) but opposite in direction hence nullifying each other's effect.
Air resistance is forcing the bird backward while earth's gravitational field attracting it downward by a force weight = mg (where m= mass of body ; g=gravitational acceleration = 9.8m/s^2).
Bird is putting force to overcome these two forces and eventually maintaining a uniform speed and constant height