Answer:
β₂ = 88.8 dβ
Explanation:
The intensity of the sound is
β = 10 log (I / I₀)
The sensitivity threshold (I₀) for humans is 1 10⁻¹² W / m²
I = I₀ 
I = 10⁻¹² 10^{70/10}
I = 1 10⁻⁵ W / m²
The total intensity for the 76 trombones is
I_total = n I
I_total = 76 1 10⁻⁵
I_total = 76 10⁻⁵ W / m²
Let's find the sound level
β₂ = 10 log (76 10⁻⁵ / 10⁻¹²)
β₂ = 88.8 dβ
Yes it does. But not always
Answer:
It is<em> impossible</em> to construct a machine which produces the <em>work output greater than the work input.</em>
Let us consider the II law of thermodynamics.
According to Kelvin Plank's statement any engine/machine does not give hundred percent efficiency. And violating the PMM-II(Perpetual motion of machine II kind), Always some amount of energy transferred to the sink or surroundings.
Therefore
W(ouput) = Q₁-Q₂
There are many reasons to lower the work output, just for an example friction between the mating parts reduces the work output.
Answer:
D. 4Al + 3O2 → 2Al2O3
Explanation:
Chemical reactions involves the chemical combination of two or more substances called REACTANTS to yield other substances called PRODUCTS. However, in accordance with the LAW OF CONSERVATION OF MASS, the amount of reactants must be equal to that of the products.
To accomplish this, the reaction must be BALANCED. A balanced equation is an equation in which the number of atoms of each element in the reactant side equals the number of atoms in the product side. In this reaction involving Aluminum and Oxygen to give Aluminum oxide as follows:
Al + 02 → Al2O3
A coefficient is used to balance the number of atoms on both sides of the equation as follows:
4Al + 3O2 → 2Al2O3
The answer is C. Electrical;mechanical
