Answer:
Explanation:
Given
Airplane is flying with horizontally with a constant momentum during time interval 
Impulse is given by change in momentum, so there is no net impulse on the Plane because momentum is constant
(b) As there is no change in momentum therefore impulse of thrust and air drag is balanced i.e. both are equal in magnitude but act in opposite direction
I'm pretty sure it's the<span> impact of the air molecules on the outside of the stopper. They exert a net inward force, which is not resisted by anything on the other side.</span>
Answer:

Explanation:
By Snell's law we know at the left surface




now we have


now on the other surface we know that
angle of incidence = 

so again we have

so we have


also we know that


By solving above equation we have

Answer:
An increase in air temperature because of its compression.
Explanation:
The Gay-Lussac's Law states that a gas pressure is directly proportional to its temperature in an enclosed system to constant volume.
<em>where P: is the gas pressure, T: is the gas temperature and k: is a constant.</em>
Therefore, due to Gay-Lussac's Law, when the plunger is pushed down very rapidly, the pressure of the air increase, which leads to its temperature increase. That is why cotton flashes and burns.
I hope it helps you!