- #1

EgpYo

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Also, do degrees have any affect on significant digits?

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- Thread starter EgpYo
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- #1

EgpYo

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Also, do degrees have any affect on significant digits?

- #2

Bystander

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Also, do degrees have any affect on significant digits?

"2000" has four significant figures; 2.00 x 103 sig digs and the mass is 2000kg

Same game.3 sig digs and the mass is 250kg

Angular measure? Temperature? Trig. functions of angular measure?Also, do degrees have any affect on significant digits?

- #3

EgpYo

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I mean if the questions says something like: "Object is moving 14.0m/s at an angle 7 degrees above the horizontal. Would the final answer have 3 or 1 significant figures?

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EgpYo

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I thought "2000"

If the direction is in some way involved in calculations, yes. If it's so much window dressing, no.14.0m/s at an angle 7 degrees

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That is not a correct statement of significant figures; only two are given, and only two can be reported at the end of the calculation.1.5kg. Final answer was given with 3 significant figures, which doesn't make sense to me.

- #7

ehild

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1.5 kg is given with 2 significant digits. If you want to give it with 3 significant figures you should write 1.50 kg.

- #8

EgpYo

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Zeros at the end of a number but to the left of a decimal are significant if they have been measured or are the first estimated digit; otherwise, they are__not significant.__*(example: 2000 has just 1 significant digit)*

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It's all up to you what you want to call measured or unmeasured. Life is much easier if you get used to certain "conventions" surrounding use of the concept.if they have been measured

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vela

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That's a very poor example. The number of significant figures in 2000 is ambiguous since you don't know if the 0s are significant or merely placeholders. The use of scientific notation removes this ambiguity, and that's one reason for using it.

Keep in mind that using the lowest number of sig figs is only a rule of thumb. You can sometimes keep more digits sometimes. For example, 0.99 m + 0.01 m = 1.00 m — if the two measurements are to the nearest centimeter, adding them isn't suddenly going to cause the uncertainty to jump to the nearest decimeter. Similarly, (3.2 m)π = 10.1 m. To figure out the proper number of digits to keep, you'd really have to do error analysis.

- #11

mfb

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There are calculations where the concept of significant figures does not work any more, and a better error analysis becomes necessary.I mean if the questions says something like: "Object is moving 14.0m/s at an angle 7 degrees above the horizontal. Would the final answer have 3 or 1 significant figures?

For example, the horizontal velocity here is 14.0m/s * cos(7°) = 13.9m/s. You can give three significant figures as the answer does not depend much on the angle, 8° and 6° still lead to the same answer.

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