Answer:
iv) It is 9x bigger than before
Explanation:
As the amplitudes of the new speakers add directly with the original one, taking into account the phase that they have, the composed amplitude of the sound wave is as follows:
At = A + 4A -2A = 3 A
The intensity of the wave, assuming it propagates evenly in all directions, is constant at a given distance from the source, and can be expressed as follows:
I = P/A
where P= Power of the wave source, A= Area (for a point source, is equal to the surface area of a sphere of radius r, where is r is the distance to the source along a straight line)
For a sinusoidal wave, the power is proportional to the square of the amplitude, so the intensity is proportional to the square of the amplitude also.
If the amplitude changes increasing three times, the change in intensity will be proportional to the square of the change in amplitude, i.e., it will be 9 times bigger.
So, the statement iv) is the right one.
Answer:
289282
Explanation:
r = Radius of plate = 0.52 mm
d = Plate separation = 0.013 mm
A = Area = 
V = Potential applied = 2 mV
k = Dielectric constant = 40
= Electric constant = 
Capacitance is given by

Charge is given by

Number of electron is given by

The number of charge carriers that will accumulate on this capacitor is approximately 289282.
My guess would be about 10 years because stars are hot balls of light that are reflections from years ago so it would most likely take awhile
Potential energy
potential energy is the stored energy an object has, the bike is not moving and it just sitting on the hill, with the stored energy
Answer:
7500 m/s
Explanation:
We can use the equation velocity of a wave equals wavelength times frequency. Therefore, v = wavelength*f = (25 m)(300 Hz) = m/s7,500