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:
W / n = - 9133 J / mol, W / n = 3653 J / mol
, e = 0.600
Explanation:
The Carnot cycle is described by
In this case they indicate that the final volume is
V = 3V₀
In the part of the heat absorption cycle from the source is an isothermal expansion
W = n RT ln (V₀ / V)
W / n = 8.314 1000 ln (1/3)
W / n = - 9133 J / mol
During the part of the isothermal compression in contact with the cold focus, as in a machine the relation of volumes is maintained in this part is compressed three times
W / n = 8.314 400 (3)
W / n = 3653 J / mol
The efficiency of the cycle is
e = 1- 400/1000
e = 0.600
Answer:
1. at least two charged interacting parts
2. from the electric fields of charged subatomic particles
3 an arrow released from the bow
4Electrical fields of charged particles interact, bonding those with opposite charges.
5 the interaction of the electric fields of protons and electrons
6 The energy stored in the system increases.
7 Kinetic energy increases because the magnets move in the direction of the field.
8 Iron pieces accelerate toward the magnet, and the energy stored in the system decreases.
9
The energy stored in the field decreases because the magnet moves in the direction of the field.
10 The energy stored increases and then decreases.
11 The wire was not connected to the source.
12 The electromagnet will become more powerful.
the rest are written, hope this helps (:
The change in momentum of the car is 45,000 kg m/s
Explanation:
The change in momentum of an object is given by:

where
m is the mass of the object
u is its initial velocity
v is its final velocity
For the car in this problem, we have
m = 900 kg
u = 30 m/s
v = 80 m/s
Therefore, the change in momentum is:

Learn more about momentum:
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The estimation of the age of the Earth comes from scientists who studied the rock formation under the Earth's crust. They believe that during the Big Bang, the Earth, together with the other celestial bodies in the universe, were formed. Under the Earth's soil contain radioactive materials that have known decay rates. Using these rate, they undergo tests like rock dating to find the time of its existence.