PHYSICS 131 FINAL EXAM QUESTIONS AND CORRECT
DETAILED ANSWERS (VERIFIED ANSWERS) |ALREADY
GRADED A+||BRAND NEW
A student (with a "rubbed" nail in her hand) sees another nail floating in
a pan of water and decides to test to see whether is "rubbed" also. She
holds the tip of the "rubbed" nail to the tip of the floating nail (as shown)
and sees that there is an attraction between them. What can she
concluded from just this observation? Ans✓✓✓ It is not possible to say
whether the floating nail has been rubbed or not.
The South Pole of a bar magnet is slid across a nail from its tip end to its
head end. The same process is repeated several times. How would you
now describe the nail? Ans✓✓✓ The nail is magnetized with its tip end
a South Pole and its head end a North Pole.
Based on our observation in class, what kind of objects could be
involved in magnetic effects? Choose the best answer. Ans✓✓✓ only
certain metals.
According to the alignment of tiny magnets model, which of the
following drawings is the best representation of an unmagnetized nail.
Ans✓✓✓ scrambled N and S Poles (facing different directions).
Imagine rubbing a small nail and a large nail with the same magnet in
exactly the same way. When each magnetized nail is then brought the
same distance from a magnetic compass, the larger nail causes the
compass needle to rotate further away from North than the smaller nail.
This means that the larger nail has greater magnetic strength than the
, smaller nail. Use the 'tiny magnets' model to explain why. Ans✓✓✓ In
the tiny magnets model, an unmagnetized nail has many 'tiny magnets'
that each have a North and South pole. These 'tiny magnets' are flipped
all kinds of ways, pointing their north and south poles in different
directions, causing there to be no magnetization. Bigger nails have more
'tiny magnets' inside of than compared to smaller nails.
In this example, the larger nail is proven to have greater magnetic
strength, since it made the compass needle rotate further than the smaller
nail. This is because the bigger nail has more "tiny magnets' inside.
Since the bigger nail has more 'tiny magnets,' when the nail is
magnetized, they all come together and point their poles to the correct
end poles of the nail, causing the magnetization strength to increase
dramatically. Although the smaller nail has 'tiny magnets,' when they
line up correctly after the small nail is rubbed by a magnet, they don't
have as much magnetic strength, because there are not as many 'tiny
magnets' in the smaller nail, since the size of the smaller nail doesn't
allow it.
When a magnetized nail is cut into pieces, is each piece one-sided, two-
ended, or something different, or does the result depend on exactly
where the nail is cut? What evidence supports your answer? Ans✓✓✓
Two-ended. When a magnetized nail is cut into pieces, the pieces can
still be magnetized, which in turn gives each end of the broken piece of
nail poles. Since the nail is broken in half, there are less 'tiny magnets,'
which can cause the broken pieces to not have as strong of a magnetic
strength.
Below are two statements about contact push/pull interactions. Read
each statement carefully and decide which statements, if any, are true.
DETAILED ANSWERS (VERIFIED ANSWERS) |ALREADY
GRADED A+||BRAND NEW
A student (with a "rubbed" nail in her hand) sees another nail floating in
a pan of water and decides to test to see whether is "rubbed" also. She
holds the tip of the "rubbed" nail to the tip of the floating nail (as shown)
and sees that there is an attraction between them. What can she
concluded from just this observation? Ans✓✓✓ It is not possible to say
whether the floating nail has been rubbed or not.
The South Pole of a bar magnet is slid across a nail from its tip end to its
head end. The same process is repeated several times. How would you
now describe the nail? Ans✓✓✓ The nail is magnetized with its tip end
a South Pole and its head end a North Pole.
Based on our observation in class, what kind of objects could be
involved in magnetic effects? Choose the best answer. Ans✓✓✓ only
certain metals.
According to the alignment of tiny magnets model, which of the
following drawings is the best representation of an unmagnetized nail.
Ans✓✓✓ scrambled N and S Poles (facing different directions).
Imagine rubbing a small nail and a large nail with the same magnet in
exactly the same way. When each magnetized nail is then brought the
same distance from a magnetic compass, the larger nail causes the
compass needle to rotate further away from North than the smaller nail.
This means that the larger nail has greater magnetic strength than the
, smaller nail. Use the 'tiny magnets' model to explain why. Ans✓✓✓ In
the tiny magnets model, an unmagnetized nail has many 'tiny magnets'
that each have a North and South pole. These 'tiny magnets' are flipped
all kinds of ways, pointing their north and south poles in different
directions, causing there to be no magnetization. Bigger nails have more
'tiny magnets' inside of than compared to smaller nails.
In this example, the larger nail is proven to have greater magnetic
strength, since it made the compass needle rotate further than the smaller
nail. This is because the bigger nail has more "tiny magnets' inside.
Since the bigger nail has more 'tiny magnets,' when the nail is
magnetized, they all come together and point their poles to the correct
end poles of the nail, causing the magnetization strength to increase
dramatically. Although the smaller nail has 'tiny magnets,' when they
line up correctly after the small nail is rubbed by a magnet, they don't
have as much magnetic strength, because there are not as many 'tiny
magnets' in the smaller nail, since the size of the smaller nail doesn't
allow it.
When a magnetized nail is cut into pieces, is each piece one-sided, two-
ended, or something different, or does the result depend on exactly
where the nail is cut? What evidence supports your answer? Ans✓✓✓
Two-ended. When a magnetized nail is cut into pieces, the pieces can
still be magnetized, which in turn gives each end of the broken piece of
nail poles. Since the nail is broken in half, there are less 'tiny magnets,'
which can cause the broken pieces to not have as strong of a magnetic
strength.
Below are two statements about contact push/pull interactions. Read
each statement carefully and decide which statements, if any, are true.
