Answer:
The correct option is;
B. 8 m, because he has to apply less force over a greater distance
Explanation:
In the given question, in order for the student to lift the boxes onto the tuck with less amount of force, he applies the principle of Mechanical Advantage
The mechanical advantage is given by the measure by which a force is amplified through the use of a tool
Given that the work done = The force × The distance, we have
F₁ × d₁ = F₂ × d₂, which gives;
d₁/d₂ = F₂/F₁
Where;
F₁ = The input force
F₂ = The output force
d₁ = The input distance
d₂ = The output distance
The Mechanical advantage, MA = d₁/d₂ = F₂/F₁
Therefore, when the input distance is increased the input force will be reduced for a given output force
Words less true are seldom if ever spoken.
Answer:
As you may know, each element has a "fixed" number of protons and electrons.
These electrons live in elliptical orbits around the nucleus, called valence levels or energy levels.
We know that as further away are the orbits from the nucleus, the more energy has the electrons in it. (And those energies are fixed)
Now, when an electron jumps from a level to another, there is also a jump in energy, and that jump depends only on the levels, then the jump in energy is fixed.
Particularly, when an electron jumps from a more energetic level to a less energetic one, that change in energy must be compensated in some way, and that way is by radiating a photon whose energy is exactly the same as the energy of the jump.
And the energy of a photon is related to the wavelength of the photon, then we can conclude that for a given element, the possible jumps of energy levels are known, meaning that the possible "jumps in energy" are known, which means that the wavelengths of the radiated photons also are known. Then by looking at the colors of the bands (whose depend on the wavelength of the radiated photons) we can know almost exactly what elements are radiating them.
The answer is polarization. It is just like when you are on a boat and use polarized glasses so the water wont reflect into your eyes it also intensifies the color of the water so you can see better into the water.
example: you cant see any fish because glare from the sun, put on polarized glasses and now you can see fish up to 30 feet deep.
The half life is 30 minutes.
30 mins- 1/2 left
60 mins- 1/4 left
90 mins- 1/8 left
120 mins- 1/16 left
120 mins= 2 hours
