Calculations Made Easy for Beginners

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The discussion focuses on simplifying calculations for beginners, particularly in estimating surface area and energy. Participants emphasize the importance of unit conversion, noting that surface area should be calculated correctly to avoid errors. A specific example is provided, calculating the surface area of a person based on height and width, but highlights a mistake in converting from cm² to m². Additionally, the conversation reminds users to consider that only one side of a person is exposed to sunlight when performing energy calculations. Accurate unit handling and understanding the context of the calculations are crucial for beginners.
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Thank you <3
 
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How about you start with question a)
It's an estimate, so go look in a mirror... as long as you don't come up with 5 cm² or 12 m² or something in m³ or kW/m you're fine.

For b), I think the question is fairly straightforward. But if you have no idea, you can look at the units. You are given something in J/(s m²), something in m² (from a) and something in s (a duration is given in the question). The units you need to have are J (Joules, you are asked for an energy). How can you combine these?
 
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Acstars said:
For a if the average height was 170cm and the width is 30cm.
Surface area = height X width
SA = 170 X 30
SA = 5100cm
SA = 51m^2
It seems pretty off though?

5100cm² seems right, but there is an issue in your conversion to m².
 
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Kindly see the attached pdf. My attempt to solve it, is in it. I'm wondering if my solution is right. My idea is this: At any point of time, the ball may be assumed to be at an incline which is at an angle of θ(kindly see both the pics in the pdf file). The value of θ will continuously change and so will the value of friction. I'm not able to figure out, why my solution is wrong, if it is wrong .
TL;DR Summary: I came across this question from a Sri Lankan A-level textbook. Question - An ice cube with a length of 10 cm is immersed in water at 0 °C. An observer observes the ice cube from the water, and it seems to be 7.75 cm long. If the refractive index of water is 4/3, find the height of the ice cube immersed in the water. I could not understand how the apparent height of the ice cube in the water depends on the height of the ice cube immersed in the water. Does anyone have an...
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