Most appropriate unit of measurement should be centimetres, cm.
Answer:
Relative to the ground, the velocity of the aircraft is 240 km/hr
Explanation:
Relative velocity is different from normal velocity;
When 2 objects are moving in opposite directions towards each other, they will appear to be faster than they actually are;
This is known as the relative velocity;
The information tells us we have the aircraft moving 320 km/hr northwards relative to the wind;
The wind is in the opposite direction at 80 km/hr;
R = relative velocity of the aircraft
v = actual velocity of the aircraft
w = velocity of the wind
R = v + w
Note: if the wind was moving in the same direction, the formula would be R = v - w
320 = v + 80
v = 320 - 80
v = 240
The velocity relative to the ground is simply the actual velocity as the ground doesn't move;
So, relative to the ground, the velocity of the aircraft is simply 240 km/hr
We know that the change in momentum is equals to the product of force and time that is impulse ( 
). Therefore, we need to determine the value of that the water is in air by using the second equation of motion,
Here, u is initial velocity which is zero.
.
Thus, impulse
From Newton`s second law,
Therefore, impulse
Given, 
and 
Substituting these values, we get
Change in momentum = impulse
.
