To solve this problem we will apply the concepts related to relative speed. We will obtain it from the deduction made on the aircraft as a speed of the two components that act on it. Through the kinematic equations of motion, we can then calculate the time required.
The airspeed of airplane is 100km/h while the wind is blowing from the coast out to sea at 40km/h. Wind is blowing from the coast out to sea means that it opposes the airspeed. Therefore, resultant relative speed of airplane is
[tex]v_r = 100-40=60km/h[/tex]
Total distance is 60km then with this net velocity we have that the required time is
[tex]v = \frac{x}{t} \rightarrow t = \frac{x}{v}[/tex]
Where,
x = Displacement
t = Time
v = Velocity
Replacing,
[tex]t = \frac{60km}{60km/h} = 1hour[/tex]
[tex]t = 60 minutes[/tex]
Therefore the time taken by the plane to reach the shore is 60 minutes
