By using Ohm's law, we can calculate the resistance of the wire. Ohm's law states that:

where V is the potential difference across the conductor, I is the current and R the resistance. Rearranging the equation, we get

Now we can use the following equation to calculate the length of the wire:

(1)
where

is the resistivity of the material
L is the length of the conductor
A is its cross-sectional area
In this problem, we have a wire of copper, with resistivity

. The radius of the wire is half the diameter:

And the cross-sectional area is

So now we can rearrange eq.(1) to calculate the length of the wire:
Answer:
v = 4.4 m / s
Explanation:
Unfortunately, the exercise scheme does not appear. Let's analyze the problem the marble leaves point A with an initial velocity, goes down and then rises to a given height where its velocity is zero, in the whole trajectory they tell us that the resistance is zero, so we can use the conservation relations of the enegy.
Starting point. Point A
Em₀ = K + U = ½ m v2 + mg y_a
point B.
Em_f = U = m g y
the energy is conserved
Em₀ = Em_f
½ m v² + mg y_a = m g y
½ m v² = m g (y -y_a)
v =
In the exercise the diagram is not seen, but the height of point A must be known, suppose that y_a = 4 m
v =
v = 4.4 m / s
<h3><u>
Answer;</u></h3>
B) Not Balanced
B) Sodium
B) Not Equal
The equation is <em><u>not balanced</u></em> because the number of <em><u>sodium atoms</u></em> is <em><u>not equal</u></em> on both sides of the arrow.
<h3><u>Explanation;</u></h3>
- <em><u>According to the law of conservation of mass, the mass of reactants should always be the same as the mass of the products in a chemical equation.</u></em> Therefore, the number of atoms of each element in a chemical equation should always be the same on both sides of the equation, that is the side of reactants and side of products.
- Therefore,<u><em>any chemical equation requires balancing to ensure that the number of atoms of each element is equal in both sides of the equation</em></u>. Balancing is a try and error process that ensures that the law of conservation of mass holds.
- Thus, the balanced chemical equation is;
2Na + Cl2 → 2NaCl
The Second Law of Thermodynamics states that the state of entropy of the entire universe, as an isolated system, will always increase over time.
Take that as you will