Not sure but just coming to say good luck and take your time
Answer:
The answer is: letter c, density.
Explanation:
Gold is a chemical element that is <em>very rare.</em> It has a high atomic number and is represented by the symbol "Au."
The problem above is asking about the physical property of gold that will help you determine whether a shiny gold nugget is, indeed, real gold. Remember that you are hiking and not anywhere else in the world.
If you look at choice a, appearance. This is definitely incorrect because looking at the object will not be able to help you verify whether it is true gold or "fool's gold." Considering melting point (letter b) would also be hard because you will be needing the necessary equipment to melt gold. Gold melts at 1,064 degrees Celsius. So,this sounds very impractical. (thus, melting point is incorrect) Now, if you look at letter d, physical state, it goes the same way with appearance. It will only tell you that the object is solid and that's it.
Letter c, density is the answer because if you analyze the density of gold, which is 19.32 grams per cubic meter, it is far from the density of iron pyrite (fool's gold) which is 4.8-5 grams per cubic meter. This means that gold is denser or heavier than iron pyrite. You will definitely be able to tell which such big gap in their densities.
Answer:
19.8 J
Explanation:
According to the law of conservation of energy, the total mechanical energy of the spring (sum of kinetic energy and elastic potential energy) must be conserved:
(1)
where we have
is the initial kinetic energy of the spring, which is zero because the spring starts from rest (2)
is the elastic potential energy of the spring when it is fully stretched
is the kinetic energy of the spring when it reaches the natural length
is the elastic potential energy of the spring when it reaches its natural length, which is zero because the stretch in this case is zero (3)
So
where
k = 440 N/m is the spring constant
is the initial stretching of the spring
Substituting,
And so using eq.(1) and keeping in mind (2) and (3) we find
It is B. the potential difference is the battery is 5 V
