Answer:
The force exerted on the
is 
Explanation:
From the question we are told that
The area is 
The magnitude of charge placed on them is 
The charge placed between the plate is 
The electric field generated around the plate is mathematically represented as

Substituting values


The force exerted the charge
is mathematically represented as

Substituting values


So the question ask to formulate an expression to represent the amount of air required to inflate the balloon from a radius of R+4 and the expression would be V=16pi/3*(3r^2+12r+16). I hope you are satisfied with my answer and feel free to ask for more if you have question and further clarifications
bonsoir, je peux vous aider avec les maths laissez-moi comprendre merci
Lets assume that s is the speed of the slower train and f is the speed of the faster train.
s = f - 16
f = 150 / t
s = 170 / ( t+2 )
-----------------------
170 / ( t+2 ) = 150 / t - 16 / t * ( t + 2 )
170 t = 150 * ( t + 2 ) - 16 t * ( t + 2 )
170 t = 150 t + 300 - 16 t² - 32 t
16 f² + 52 t - 300 = 0 / : 4 ( We will divide both sides of the equation by 4 )
4 t² + 13 t - 75 = 0
t 1/2 = ( -13 + √(169 + 1200 ) )/ 8
t = ( - 13 + 37 ) / 8 = 24 / 8 = 3
t = 3 h
s = 170 : ( 3 + 2 ) = 170 : 5 = 34 mph
Answer: The speed of the slower train is 34 mph.