Answer: 0.4 km/h
100 m = 0.1 km
15min./60min. = 0.25 hr
so, divide the total distance (100 m) by the total time (15 min)
0.1 km/0.25 hr = 0.4
Explanation:
let vertical distance from A to C be 
the constraint equation is:
we want to find 
distance can be written as 
which we will find by using Pythagorean theorem h 1 is a constant and can be written as h:
taking derivative w.r.t time we get
given 
which gives us
<span>So we wan't to know what will the Coulomb force be between two charged baloons will be if we double the distance between the them and Fc=0.16N. The coulomb force between two charges is Fc=k*Q1*Q2/r^2. So we see from the equation that the magnitude of the force will be smaller as we increase the distance. So let's increase the distance from r to R=2r. If we input thai into the equation we get: Fc=k*Q1*Q2/R^2. Now: Fc=k*Q1*Q2/(2r)^2. And finally: Fc= k*Q1*Q2/4r^2. And if we factor out 1/4 we get: Fc=(1/4)*k*Q1*Q2/r^2. Now we can see that if we double the distance the magnitude of the force will be smaller for a factor of 1/4 or the magnitude of the force will be smaller 4 times. So finally the force is (1/4)*0.16N= 0.04N. So the correct answer is A. 0.04 newtons. </span>
A substance which allows the un-interrupted flow of electric current is called an electric conductor
