I believe its the law of inertia
Answer:
The tension is 
Explanation:
From the question we are told that
The total mass is 
The radius is 
The density of air is 
Generally the upward force acting on the balloon is mathematically represented as

=> 
=> 
Here V is the volume of the spherical helium filled balloon which is mathematically represented as

=> 
=> 
So


The similarity is that they both are types of bonds in molecules.
Ionic bonds are between a metal and a nonmetal.
Covalent bonds are between two nonmetals.
The answer is 15 kilometers in 20 minutes.