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Foolproof Method for Maths Questions
strong1739:
--- Quote from: RuiAce on October 29, 2016, 11:25:45 pm ---
--- End quote ---
omg tysm i didnt know that ty ty ty
armtistic:
What do you mean when you say "LOWEST significant figure" ?
RuiAce:
--- Quote from: armtistic on January 12, 2017, 11:19:10 am ---What do you mean when you say "LOWEST significant figure" ?
--- End quote ---
Suppose a question is based on projectile motion.
And it tells you that the initial velocity is v=13.4
And you know that the range is 27.05 m
But you have to use the gravitational acceleration on Earth, which is 9.8
v is at 3 s.f.
Range is at 4 s.f.
But g is at 2 s.f.
Therefore your final answer must be correct to 2 s.f.
armtistic:
--- Quote from: RuiAce on January 12, 2017, 11:21:59 am ---Suppose a question is based on projectile motion.
And it tells you that the initial velocity is v=13.4
And you know that the range is 27.05 m
But you have to use the gravitational acceleration on Earth, which is 9.8
v is at 3 s.f.
Range is at 4 s.f.
But g is at 2 s.f.
Therefore your final answer must be correct to 2 s.f.
--- End quote ---
Oh right. Why is it like that?
Like if i was trying to find the force of gravity between two objects of very large mass but the distance between them was like 1m I would only do it to 1 s.f?
RuiAce:
--- Quote from: armtistic on January 12, 2017, 03:21:12 pm ---
Oh right. Why is it like that?
Like if i was trying to find the force of gravity between two objects of very large mass but the distance between them was like 1m I would only do it to 1 s.f?
--- End quote ---
Because significant figures are a measure of accuracy
In reality, something like, say, the mass of an electron isn't just 9.109x10^-31 kg. That's a rounded figure.
Something like this, whilst not exact, would be FAR more accurate: 9.10938356 × 10^-31 kg.
If instead, our distance was given at 1.0m, we know the accuracy of our distance a bit more. 1m could've been rounded from 1.4m, which is notably longer than 1.0m. So we use the lowest given significant figures to represent the accuracy of our measurements and calculations.
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