The average density of the material from which the coin is made is 9.67 g/cm³.
<h3>Volume of the coin</h3>
The volume of the coin at the given diameter is calculated as follows;
V = Ah
where;
- A is area of the coin
- h is the thickness of the coin
V = πd²/4 x h
V = π(2.8)²/4 x (0.21 cm)
V = 1.293 cm³
<h3>average density of the coin</h3>
The average density of the material from which the coin is made is calculated as follows;
density = mass/volume
density = 12.5 g / (1.293 cm³)
density = 9.67 g/cm³
Thus, the average density of the material from which the coin is made is 9.67 g/cm³.
Learn more about average density here: brainly.com/question/1354972
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Answer:
I was also going to ask same question edited:ok i found its true
Its “A“ primary waves!!!!!!
Answer:
t = 6 minutes
Explanation:
Given that,
Force,
Initial speed of the train, u = 0
Final speed of the train, v = 80 km/h = 22.22 m/s
The mass of the train, 
We need to find the time taken by the train to come to rest. We know that,
F = ma
or
t = 6 minutes (approx)
So, the required time is equal to 6 minutes.
The answer is a bit confusing, so I did some research and fount the original question. This is the complete question:
"<span>If
measurements of a gas are 75L and 300 kilopascals and then the gas is
measured a second time and found to be 50L, describe what had to happen
to the pressure (if temperature remained constant). Include which law
supports this observation".
From that:
1) Data:
V1 = 75 liter
P1 = 300 kPa
V2 = 50 liter
P2 = x
T = constant.
2) Analysis (physical law)
Boyle's law states that the volume of a fixed amount of gas, at constant temperarature, is inversely related with the pressure.
In mathematical form that statement becomes into this equation:
PV = constant (at constant T)
=> P1V1 = P2V2.
Then, the decreasing of the volumen (compression) is accompanied by an increase of the pressure.
3) So, using Boyle's law with the data given:
300 kPa * 75 liter = x * 50 liter
=> x = 300 kPa * 75 liter / 50 liter = 450 kPa.
Answer: following Boyle's law, when the gas passed from 75 liter to 50 liter the pressure had to increase from 300 kPa to 450 kPa.
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