The mass of a is smaller than the mass of b.
I would think force. Because friction has to have force to work ^-^
They would most likely use statistics on the increase/decrease in population from previous decades and centuries. In addition to these statistics, they could use the birth and death rate and ultimately predict the increase within these next 30 years. They must also take climate change and other environmental factors into consideration when formulating such a bold prediction.
That particular group of elements is reffered to as the "Noble Gasses"--a title that comes from the fact that these gases are very "secure" and don't mix well with other elements.
Lindsay has to fly this plane towards this direction [W 12.5° S] to get to Hamilton.
From this question, the plane is still up in the air.
We have wind blowing in [W 60° N ]
To solve the problem we have to make use of the sine rule

We put the values in the equation, we have:
50/Sinθ = 200/sin60°
The next step is to cross multiply
50 x sin60° = 200Sinθ
50 x 0.8660 = 200sinθ
We make Sin θ the subject
Sine θ = 43.30/200
sine θ = 0.2165
we find the value of θ
θ = sine⁻¹(0.2165)
θ = 12.50
So Lindsay has to fly this plane towards this direction
[W 12.5° S]
Here is a similar question brainly.com/question/13338067?referrer=searchResults