Significant figures Definition and 153 Threads

Homework Statement I am starting to confuse myself with the proper use of SF. I am to convert time from minutes to hours, keeping in mind proper SF Homework Equations conversion factor: 1 min = 1/60 hr The Attempt at a Solution The timing error is +/- 0.2 (1SF) = 0.003hr (1SF) 20.0...

Homework Statement Mass of copper = 321.5 g Volume = 36 cm3 What is the density? How many significant figures should you give your density? Explain. Homework EquationsThe Attempt at a Solution The BOOK says two significant figures = 8.9 g/cm3 "since the volume is given to only two significant...

Homework Statement Solve for g in your area with the correct number of significant figures. Theta = latitude = 50.7 degrees h = height = 518. m Homework Equations g = 9.80616 - 0.025928 cos2(theta) + .00068 cos^2(2*theta) - 0.000003h The Attempt at a Solution Well, I just plugged in the data...

Hello, I have a question asking me to find the volume of a rectangular prism. The dimensions are as follows: x = 20 ± 0.2 cm, y = 30 ± 0.2 cm, z = 70 ± 0.4 cm I am asked to report the answer with the correct number of significant figures and include the error. What I have so far: V = xyz =...

Homework Statement What is the answer to (72.4meters)*(cos58)? How many significant figures does it have, and why? Homework Equations "The least number of significant figures in any number of the problem determines the number of significant figures in the answer." cos58=0.529919264233... The...

Homework Statement I've got a doppler shift question about calculating the frequency heard by a receiver moving 5.0m/s towards a sound source that is emitting 3000Hz sound. I assumed speed of sound is 343 m/s for an air temperature of 20C. Homework Equations Freceiver = Fsender((V +...

Homework Statement What mass of ethanol, C2H5OH(l), must be burned to supply 1000 kJ of heat? The standard enthalpy of combustion of ethanol at 298 K is -1368 kJ⋅mol-1, and its molecular weight is 46.07 g⋅mol-1 . I know how to solve this, but I'm unsure about the number of significant figures...

Homework Statement This is a lab question. I'll summarize with key information. Car traveling from Point A to Point B. You record the time and distance. "Since the odometer gave the distance within 100 m, you estimated the uncertainty in d to be (Δd = ±0.1 km). Regarding the time, even though...

I have a question about sig figs and how they relate to measuring. Say I am finding the velocity of a small object. From an experiment, I gather the data that the object moved .0765 meters in .07 seconds. As one can tell, my watch is less precise than my fancy ruler. Using these data, I...

Homework Statement If they ask me to find which value is more accurate: a)2000g b)2.00Kg? Homework EquationsThe Attempt at a Solution It should be b right? The book says a, 2000g = 2Kg or is it 2000g = 2.000Kg?

In most areas of science, being able to solve and report problems to the correct number of significant figures is necessary; but I'm having trouble finding a complete set of rules for significant figures when working with non-ideal power equations. eg: I'm talking about equations requiring the...

So from what I had initially understood, in a conversion problem, you go by whatever number has the smallest SF and round your answer to that number, even if that number is one. In the examples on my homework it seems like my teacher chooses a random number of significant figures for each...

Homework Statement Calculate the average speed and average velocity of a complete round trip in which the outgoing 250 km is covered at 95 km/h, followed by a 1.0 h lunch break, and the return 250 km is covered at 55 km/hThe attempt at a solution I know how to calculate average velocity and...

Homework Statement Add the following: (2.526/3.1) + (0.470/0.623) + (80.705/0.4326) 2. The attempt at a solution = (2.526/3.1) + (0.470/0.623) + (80.705/0.4326) = (0.81) + (0.754) + (186.6) = 188.2 I have calculated the answer (using sig figs) to be 188.2, however, the answer...

Hi all, Newbie here. Forgive if I'm starting this thread in the wrong place! Started college physics this semester and although the physics is not the most challenging, I'm running into lots of trouble with the sig figs! First of all, when doing long calculations, where do you round the sig...

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Physics has always been my main interest; with more than a mere "favourite subject" label. Therefore I have made it one of my goals to not only be able to solve problems, but also express rigor and detail in my calculations. With regard to solving problems, I have 2 main questions: 1)...

Homework Statement I converted 14:34:52.43 into decimal degrees which is 218.71845... My question is, how do I know how many numbers I should write after the decimal to retain the original precision? Homework Equations 1 hour = 15 degrees The Attempt at a Solution 15 (14 +...

I am trying to convert a mole quantity into a mass. ##m_{CO_2}## will represent mass, ##M_{CO_2}## will represent molar mass and ##n_{CO_2}## will represent mole quantity. I have ##n_{CO_2} = 3.3## and ##M_{CO_2} = (12.01 + 2(16.00))## So, ##m_{CO_2} = 3.3(12.01 + 2(16.00))## If I compute...

Homework Statement A 200. kg sample of MgO is given (Notice 3 sig figs). How many kg of magnesium ions would there be? Homework Equations %Mg = 62% %O = 38% The Attempt at a Solution Just a quick question I had about significant figures. The sample of MgO given is 200.kg (3 sig figs). The...

We have a right triangle with sides of length 735 and 420 m where the intermediate angle of aforementioned sides is 50°. The task is simple: Calculate |AB|. Here is a picture: Upon calculating |AB|, we arrive at approximately 565.48 m. My problem is how many significant figures one ought to...

I received an excellent question about significant figures when there is no actual numerical data given. In the figure below, we have a cube circumscribing a triangle and the task is to find the angle at M. N and M are midpoints of the cube's side. By using the Pythagorean theorem a few times...

Homework Statement what is 33.3 X 45.1 using significant figures?Homework Equations basic multiplication and significant figures. The Attempt at a Solution I got 1501.83 in my calculator. I'm confused with the original problem because it has 4 digits before the period however you have to...

I have a question which states that a car's speed is 110km/h. Should I assume this speed to be 3 significant figures or 4 significant figures? why??

I do not fully understand significant figures. It seems the physics textbooks ignore their own significant figure rules, eventually. For this problem when I divide 2.3 m by 1.0 s, I get 2.3 m/s, but the answer in the book is 2.30 m/s. In another situation I am divding 48.3 m by 3.0 s to get 16.1...

After losing marks in an exam due to significant figures, I have decided to clear up all my doubts about this concept. But since my teacher hasn't been very helpful, I've decided to post my question here. I understand the rules for significant figures in both single-step...

I'm hoping for verification here that I'm not crazy on some very very basic chemistry questions. I've worked 7 problems on a practice test (the real thing is next Tuesday). Only 2 of my answers agree with the answer key. Here are the most dramatic examples. Please tell me I'm not crazy...

Dear Forum, why do calculators always give an incorrect number of significant figures? What assumptions do they make? thanks fisico30

Engineering in Higher Education -- significant figures I am currently in my 4th semester. It seems that every engineering textbooks I encounter have no regard of significant figures (SF). Every problems and examples I encounter are like that. Mostly integers, some have decimal figures, but...

Why are zeroes following a non-zero number in the decimal area considered significant? 2.34000 <-- Like this, why are the three zeroes after the four considered significant?

Hi! I'm confused, please I would love some help with this: Homework Statement if the inner radius of a ring is 3,56 cm and the outer radius is measured as 3,32 cm, compute the area of the ringHomework Equations When multiplying the number of significant figures stays the same, when adding or...

In any physical measurement we often refer to two terms... 1.'Order of Magnitude' of certain quantity 2.the number of 'Significant figures' What they actually mean?

Can you give me the answer to the right significant number please? I got R_L(max) = 0.0022 [ohm] and R_L(min) = 0.3 [ohm] but I have a feeling that they're not correct. Someone please check. R_L(max) = |(5 - 2.4)/(3*(-400) + 40))| R_L(min) = (5 - 0.4)/(16 - (-1.6))

Dear all, Me and my friends are arguing how many significant figures does 0.0 and 0.0000 have? Me and my other friend say it does not have any significant figure and the others say it's 1 significant number and exact, a special case. Please advise for the correct one. Thanks!

Hi everyone, i have a doubt about significant figures, on a book I read this: "When multiplying several quantities, the number of significant figures in the final answer is the same as the number of significant figures in the quantity having the lowest number of significant figures. The...

2340-100 For addition/subtraction problems you are supposed to use the number with the fewest digits to the right of the decimal point, but in this case, there are no decimals. My teacher gave an answer of 2200. Why is this the case instead of 2240 or 2000?

One thing I have always questioned is this: Teachers always tell us that a final answer should never have any more significant figures than the least number of sig figs on a measured value used. But something doesn't add up here... Suppose you knew the length of a metal rod to be...

Hello physicsforum people, I'm not sure how many significant figures I should express a confidence interval to. I have confidence intervals for means that I need to express in a lab report, which I am going to do in the something ± something fashion. (I have assumed a normal distribution of...

Homework Statement A student is running at her top speed of 5.0 m/s to catch a bus, which is stopped at the bus stop. When the student is still 40.0 m from the bus, it starts to pull away, moving with a constant acceleration of 0.170 m/s2. For how much time and what distance does the...

Let’s say I have a class A 25ml pipet with an uncertainty of +/- 0.24ml. If I want to express the volume of the pipet to the correct number of sig figs to say determine the sig figs in a final answer - what is it? Is it 25 ie two, because that is the marking? Or 25.00 ie four...

A book says," 0.00052 has two significant figures: 5 and 2" Now imagine a scale to measure length and suppose it's least count is 0.00005 we measure a length and it comes out to be 0.00052 where we are uncertain about the last digit. So if i am understanding the meaning of sig. figures right...

Homework Statement A student makes measurements from which she calculates the speed of sound as 327.66ms–1. She estimates that her result is accurate to ±3 %. Which of the following gives her result expressed to the appropriate number of significant figures? A 327.7ms–1 B 328ms–1 C 330ms–1 D...

SOLVED: Significant figures in seconds to hours calculation Homework Statement Not exactly a problem, but if I have minutes/seconds and am changing to hours, how many significant figures are there? For example: 29 minutes 57 seconds =0.499166667 hours needs ? significant figures. The...

Homework Statement So I'm determining the specific heat capacity of brass for a lab report, when i initially measured temperature it was to two significant figures (this was the measurement with the least significant figures) My final answer, remarkably was 0.38 (j/g*K) but my error was...

Having a discussion with a colleague over sig figs and conversions. Original problem: find perimeter of 12.6 ft by 13.88 ft room and express answer in meters. 16.1 m or 16.2 m? Question is when to round? After finding perimeter in feet? 53.0 feet to meters = 16.2 meters or at the...

Homework Statement The side of a cube is 12.04 cm. Write it's surface area rounded off to the appropriate significant figures. Homework Equations Surface area=6 x side^2 For multiplying, the answer should be written with the number of significant figures equal to the least number of...

A rectangular plate has a length of (21.3\pm0.2) cm and a width of (9.80\pm 0.1) cm. Find the area of the plate and the uncertainty in the calculated area. Solution Area = lw = (21.3\pm0.2 cm) X (9.80\pm0.1 cm) \cong(21.3 X 9.80 \pm 21.3 X 0.1 \pm 0.2 X 9.80) cm^2...

1) Which is right? 65m/s x 3.2 s = 208 m or 65m/s x 3.2 s = 2.1 x 10^1 m2) is 210 - 3 s.f. or 2 s.f. ? 3) my teacher uses the question as a guide for s.f., is that correct? e.g. A projectile is fired with an initial speed of 1.12 s at a...

Homework Statement if error was found out to be plus/minus 58 and observed value was 227.32 how should the data be rounded of( to which significant figure) Homework Equations The Attempt at a Solution

hi we did an experiment at school and in my homework i am asked to justify the number of significant figures for x. what do they mean with justify here? i don't understand the question. my x value has 3 s.f. thanks in advance