<h3>
Answer:</h3>

<h3>
General Formulas and Concepts:</h3>
<u>Math</u>
<u>Pre-Algebra</u>
Order of Operations: BPEMDAS
- Brackets
- Parenthesis
- Exponents
- Multiplication
- Division
- Addition
- Subtraction
<u>Physics</u>
<u>Energy</u>
Elastic Potential Energy: 
- U is energy (in J)
- k is spring constant (in N/m)
- Δx is displacement from equilibrium (in m)
<h3>
Explanation:</h3>
<u>Step 1: Define</u>
k = 7.50 N/m
Δx = 0.40 m
<u>Step 2: Find Potential Energy</u>
- Substitute in variables [Elastic Potential Energy]:

- Evaluate exponents:

- Multiply:

- Multiply:

Answer:
1/ As a metal has higher melting point than a nonmetal has, we can guess that sample A is a metal.
2/ The melting point is over 1000 gradius Celcius: 1083 - it's not a low value. And as the sample conducts heat, it is not the element of period N3 in the periodic table, because elements in period 3 do not conduct electricity.
Explanation:
I can not see what the questions 2-3 in your picture is. I answered the question above the table: What can the student conclude about thenidentity of Sample A.
Answer:
It would not be possible the cohesion among water molecules by the polar covalent bonding.
Well, to understand this in a better way, let's begin by explaining that water is special due to its properties, which makes this fluid useful for many purposes and for the existence of life.
In this sense, one of the main properties of water is cohesion (molecular cohesion), which is the attraction of molecules to others of the same type. So, water molecule (
) has 2 hydrogen atoms attached to 1 oxygen atom and can stick to itself through hydrogen bonds.
How is this possible?
By the polar covalent bonding, a process in which electrons are shared unequally between atoms, due to the unequal distribution of electrons between atoms of different elements. In other words: slightly positive and slightly negative charges appear in different parts of the molecule.
Now, it can be said that a water molecule has a negative side (oxygen) and a positive side (hydrogen). This is how the oxygen atom tends to monopolize more electrons and keeps them away from hydrogen. Thanks to this polarity, water molecules can stick together.
The question can be solved using conservation of linear momentum.
= 0.06kg and
= 0.03kg
Let the initial velocity of Marble A be ,
= 0.7m/s
Let the initial velocity of Marble B be,
= 0m/s
Let the velocity of Marble A after collisiong ,
= -0,02m/s
Let the velocity of Marble B after collision be 
From the conservation of linear momentum equation. We get,

Substituting the values we get,
(0.06)(0.7) + 0 = (0.06)(-0.02) + (0.03)
we get,
= 1.44m/s
Answer:
Explanation:
For the problem, we should have same reynolds number
ρvd/mu = constant
1000×1×10⁻³×0.3×10⁻³/1.002×10⁻³ = 1400×0.5×d/600
d = 25.66 cm