Answer:

Explanation:
The amplitude of he combined wave is:

A, is the amplitude from the identical harmonic waves
B, is the amplitude of the resultant wave
θ, is the phase, between the waves
The amplitude of the combined wave must be 0.6A:

The answer is:
d) the sound originates from a vibration.
The explanation:
The sound waves are generated by a sound source, such as the vibrating diaphragm of a stereo speaker. The sound source creates vibrations in the surrounding medium. As the source continues to vibrate the medium, the vibrations propagate away from the source at the speed of sound, thus forming the sound wave.
V^2=u^2 +2aS
U is found first by considering that first 8 secs and using v=u+at. {different v and u though}
V=-u+gt.
Magnitude of u = magnitude of v if there is no resistance ( because the conservation of energy says the k. E. must be the same when it passes you as when it left your hand).... up is negative here, down is positive.
V+v=gt
2v= g x 8
V=4xg.= the initial velocity for the next calculation
V^2=(4g)^2+(2xgx21)
So v can be calculated.
The magnitude of the electrical force between a pair of charged particles is 4 Times as much when the particles are moved half as far apart.
This can be easily understood by Columb's law,

which state's that the amount of electrical force experienced by two charged particles is inversely proportional to the square of the distance between them.
∴ 
Now, we know the new distance is half the original distance,


The electrical force of attraction or electrostatic force of attraction between two charged particles refers to the amount of attractive or repulsive force that exists between the two charges. This can be calculated by Columb's Law.
A charged particle in physics is a particle that has an electric charge. It might be an ion, such as a molecule or atom having an excess or shortage of electrons in comparison to protons. The same charge is thought to be shared by an electron, a proton, or another primary particle.
Learn more about electrical force here
brainly.com/question/2526815
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To solve this problem it is necessary to use the concepts related to the Hall Effect and Drift velocity, that is, at the speed that an electron reaches due to a magnetic field.
The drift velocity is given by the equation:

Where
I = current
n = Number of free electrons
A = Cross-Section Area
q = charge of proton
Our values are given by,






The hall voltage is given by

Where
B= Magnetic field
n = number of free electrons
d = distance
e = charge of electron
Then using the formula and replacing,

