This is a diagram from above, the air resistance is oppose to movement, the bird is moving forward given its force is bigger.
Answer:
<h2>320</h2>
Just use F =ma where m is mass and a is acc.
Vì khi chiếu tia tới vuông góc một mặt phẳng gương, tia tới trùng với pháp tuyển, góc tới bằng góc phản xạ bằng 0.
V=d*t
Since d=75km=75000m
t=1.5h=3600*1.5= 5400s
=>V=75000*5400
=405000000m/s=4.05*10^8m/s