Which statement best describes energy in an open system? (2 points) All energy and matter are contained within the system. Energ
2 answers:
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a) Potential difference needed: 10,000 V
b) Because the potential difference in the house is maximum 230 V
Explanation:
a)
The relationship between current, potential difference and resistance in a conductor is given by Ohm's law:
where
V is the potential difference
R is the resistance
I is the current
The resistance of the human body is estimated to be as high as for a dry body and as low as
for a wet body: in this problem, we use a value in the middle,
Therefore, the potential difference needed to produce a current of
is
b)
Here we want to estimate if it is likely or not to get injured by an electric current in a house.
The amount of current that can be fatal is . From part a), we saw that in order to produce this current through the human body, a potential difference of
is needed.
However, the electricity that reaches the houses and then is connected to the household appliances has a potential difference of
V = 230 V
This value is much lower than 10,000 V, therefore the electricity in the house is unlikely to cause injures to human body.
Learn more about potential difference:
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Complete Question
The image for this question is shown on the first uploaded image
Answer:
Explanation:
From the question we are told that
The mass of the collar is
The original length is
The spring constant is
Generally the extension of the spring is mathematically evaluated as
Now with Pythagoras theorem we can obtain the length from A to B as
The extension of the spring at B is
According to the law of energy conservation
The energy stored in the spring at point A + the kinetic energy of the spring = The energy stored on the spring at B
So
substituting values
=>
