Answer:
The answer to your question is letter A. r = 1.07 x 10⁻¹⁴ m
Explanation:
Data
F = 2 N
d = ?
q = 1.6 x 10 ⁻¹⁹ C
k = 8.987 Nm²/C²
Formula

Solve for r

Substitution

Simplification
r = 
r = 
Result
r = 1.07 x 10⁻¹⁴ m
Hello,
Your answer to this problem is 400/3
Hope this helps!
The answer for this question is Control Variable because it doesn’t change throughout the experiment.
Answer:
We have to show surface area
,with few conditions that is by considering Force
and Pressure
to be respectively.
Explanation:
The atmospheric pressure is
on Earth's surface.
The magnitude of the force exerted on a person by the atmosphere is
.
Now to calculate surface area we can find it from
and re-arranging it to.

So plugging the values,
Surface area 
Hence from the above calculations we can say that surface area is
.
So the surface area of an average person can be said to have
, using the concept of pressure and force.
Answer:
2 in front of water and 1 in front of oxygen
Explanation:
This question is describing balancing a chemical reaction. A balanced chemical reaction has the same number of atoms of each elements on both the reactant and product side. According to the question, the reactants contains 4 atoms of oxygen. The reactants give rise to water (H20) and O2 in the products side.
This reaction is most likely the decomposition of hydrogen peroxide (H2O2) as follows:
H2O2 (l) ----> H2O (l) + O2(g)
Based on the description, H2O2 will be 2H2O2 as it is said to contain four atoms of oxygen. This means that, in order to have a balanced equation, we must place coefficient 2 in front of water and coefficient 1 in front of oxygen. That is;
2H2O2 (l) ----> 2H2O (l) + O2(g)