Exam Questions on Physics: A Grade 11 Student's Request for Answers | 1-6

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In summary, the student is asking for help with answering multiple questions related to physics. They are unsure about the calculation for finding the average of 4 numbers, but have followed the significant figure rules. They also need help identifying examples of Newton's third law and determining the true statement about the gravitational field strength of Earth. They incorrectly guess that normal force does not contribute to kinetic friction and that the angle of a reflected ray is 56 degrees. Finally, they ask for help finding the critical angle of ethyl alcohol in air.
  • #36
So it's the strongest at the bottom of the ocean then? But the bottom for some reason had a greater radius than the one at the poles... and of course the ocean floor at the poles would be the smallest radius I think... I think I'm confused...
 
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  • #37
Byrgg said:
So it's the strongest at the bottom of the ocean then? But the bottom for some reason had a greater radius than the one at the poles... and of course the ocean floor at the poles would be the smallest radius I think... I think I'm confused...
The deepest part of the ocean refers not to the distance from the sea floor to the centre of earth; but rather the depth below the surface of the water.
 
  • #38
Yeah I know that much, but wouldn't you automatically assume that the bottom of the ocean right next to the poles would be lowest? Assuming that the poles are closer to the center than the equator?
 
  • #39
Byrgg said:
Yeah I know that much, but wouldn't you automatically assume that the bottom of the ocean right next to the poles would be lowest? Assuming that the poles are closer to the center than the equator?
The lowest point in relation to the centre of the Earth is not necessarily the deepest point in the oceans.
 
  • #40
Yes I know that much, because the deepest point could be right around the equator or something, right? But if you take the poles, I'd think the oceans next to them would be deeper than the poles themselves, after all the distance to the center doesn't vary greatly in this manner unless you look at the poles compared to the equator, right?
 
  • #41
Byrgg said:
Yes I know that much, because the deepest point could be right around the equator or something, right? But if you take the poles, I'd think the oceans next to them would be deeper than the poles themselves, after all the distance to the center doesn't vary greatly in this manner unless you look at the poles compared to the equator, right?
Yes you are correct.
 
  • #42
So the greatest distance would'nt really be exactly at a pole unless there was water there, right? I'm not too up on my geography... is it only the south pole that has actual land mass on it? Or does the north pole have some too?
 
  • #43
My major point in this is that you would have no idea of these value or facts for your examination, nor would you be expected to. Therefore, the expected answer would be the deepest part of the ocean. And yes, only the south pole is a land mass. The arctic circle is floating ice.
 
  • #44
The deepest part of the ocean where exactly? On all of earth? Or the one near the poles like I said?
 
  • #45
The deepest part of the ocean (i.e. the greatest depth below the surface of the water) is the Marianas Trench in the Pacific Ocean, which is the point I discussed above.
 
  • #46
No... ugh, it's kind of hard to explain my thinking here... The deepest part of the ocean is as you said at Mariana's Trench, in the entire world... but since the poles are closer to the center of the earth... wouldn't the deepedt point there be the one closest to the earth? I'm not debating what you said that is indeed the greatest depth below the surface of the water, but I'm simply saying that deepest area at the poles is likely the one closest to the centre of the earth... as you said however, this is not necessarily the deepest point in the water. Did that clear up what I meant? I'm not too sure if I wasn't being specific enough at first or what... but that's more what I was thinking.
 
  • #47
Byrgg said:
No... ugh, it's kind of hard to explain my thinking here... The deepest part of the ocean is as you said at Mariana's Trench, in the entire world... but since the poles are closer to the center of the earth... wouldn't the deepedt point there be the one closest to the earth? I'm not debating what you said that is indeed the greatest depth below the surface of the water, but I'm simply saying that deepest area at the poles is likely the one closest to the centre of the earth... as you said however, this is not necessarily the deepest point in the water. Did that clear up what I meant? I'm not too sure if I wasn't being specific enough at first or what... but that's more what I was thinking.
Yes, I understand what your saying, and it is exactly what I was saying, obviously not very well. You are correct, the deepest part of the ocean at the polar regions will be closer to the centre of the Earth that the deepest ocean in the world. At least that's my take on it (I am no expert, perhaps a geologist could comment). However, I was also saying that your probably wouldn't be required to know this for the your exam and therefore, the expected answer would be 'the deepest part of the ocean'; at least that is my take on it. Perhaps, this will be confirmed or refuted once you get your marks back.
 
  • #48
Yeah, for simplicity, the teacher probably would expect us to take the Earth as a sphere, even though we know otherwise... for simplicity, like I said.
 
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