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.
Transverse waves are always characterized by particle motion being perpendicular to wave motion. A longitudinal wave is a wave in which particles of the medium move in a direction parallel to the direction that the wave moves.
Answer:
A) Earth and the other inner planets have higher average surface temperatures than the outer planets.
Explanation:
the earth and the other inner planets have higher average surface temperatures than the outer planets.
The reason for this response is due to the distance between the sun and the respective planet, the source of energy generation is the sun and the only way in which the temperature increase of each planet is guaranteed is by radiation, the further away a planet is from its star, its temperature will decrease. Although it is also important to highlight the atmospheric composition of the planet if this planet in its stratosphere has high density clouds that do not allow the entry of solar radiation, the temperature of the planet's surface will not increase, independent of the distance from the sun, but these are more complex cases where specialists in that area enter to perform a study in detail.
First, convert all the km/hr into m/s
You will get that
initial speed = 20 m/s
Initial speed of Green train = 40 m/s
Initial separation = 950 m
Velocity of approach = 20 - -40 = 60 m/s
relative acceleration = -4 m/s^2
v = u + at
0 = 60 - 4t
t = 15s
s = ut + 1/2 *at * t
s = 60 * 15 - 1/2 *4 * 225
s = 900 - 450
Separation when they stop = 450 m
hope this helps
