Answer:The correct options are:
1. A system is a group of objects analyzed as one unit.
2. Energy that moves across system boundaries is conserved.
Explanation:
A system is defined as group of interrelated or interacting items existing as a single unit or a whole to achieve a specific objective.Energy lost by the system is equal to the energy gained by the surroundings.
Two statements are true about a system:
- A system is a group of objects analyzed as one unit.
- Energy that moves across system boundaries is conserved.
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:
Answer:
the amount of energy flowing is 1.008x10⁹J
Explanation:
To calculate how much heat flows, the expression is the following:
Where
K=thermal conductivity=0.81W/m°C
A=area=6.2*12=74.4m²
ΔT=30-8=22°C
L=thickness=8cm=0.08m
t=time=16.9h=60840s
Replacing:
Explanation:
The marbles that are 'more energetic' fall out of the tray, in the same way particles have enough energy to escape and turn into a gas.
50(6)=300.
The ball traveled 300 meters in 50 seconds.
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