Your answer is B.
The relationship between medium temperature and speed of sound is a direct relationship: when one factor increases, the other increases as is shown in graph B. The British would choose the the time of day which would give the lowest speed of sound, because this would be easiest to break. Graph B shows that the lowest speed of sound would occur with the lowest air temperature - in the morning.
Answer:
t=0.016s
Explanation:
we can use

the time that the particle is in the magnetic field is one half oa period. Hence

I hope this is useful for you
regards
From the law of atmosphere

Where
= constant and is number density where the height y = 0cm
= Number density at height y=3cm
Kb = Boltzmann constant 


Re-arranging the equation to have the value of the gravity,


Since it is 30% of value above surface, therefore 






Therefore the correct answer is C.
The related concepts to solve this problem is the Glide Ratio. This can be defined as the product between the height of fall and the lift-to-drag ratio. Mathematically, this expression can be written as,

Replacing,


Converting this units to miles.


Therefore the glide in terms of distance measured along the ground is 7.2916miles