Unit Conversion ad Significant Figures

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SUMMARY

The discussion focuses on unit conversion and significant figures in various physics and chemistry problems. Key calculations include converting 3.99 gallons of antifreeze to tons using a density of 1.12 g/mL, determining the speed of a running back in yards per second, calculating the time a vehicle can run on 5.3 gallons of gasoline at 57 miles per hour, and estimating the number of carbon atoms in a line drawn on paper. The participants confirm the number of significant figures for each calculation, emphasizing the importance of precision in scientific measurements.

PREREQUISITES
  • Understanding of unit conversion (gallons to liters, meters to yards)
  • Knowledge of significant figures and their application in calculations
  • Familiarity with basic physics formulas (speed = distance/time)
  • Basic chemistry concepts (density, volume of atoms)
NEXT STEPS
  • Learn advanced unit conversion techniques for complex measurements
  • Study significant figures in scientific calculations and their implications
  • Explore the concept of density and its applications in real-world scenarios
  • Investigate the volume calculations for different geometric shapes in chemistry
USEFUL FOR

Students in physics and chemistry, educators teaching unit conversion and significant figures, and anyone involved in scientific calculations requiring precision.

Soaring Crane
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Unit Conversion & Significant Figures

Greetings! I would just like to re-check my work:

1) What will be the mass in tons added to a car when its radiator is filled with antifreeze (d = 1.12 g/mL) if the radiator has a capacityof 3.99 gal?

Since density = mass/volume, mass = density*volume. So I change 3.99 gal into L and then mL. After I solve for mass, the answer is in grams, so I convert to tons (g -> kg -> ton). The number of sig. figs. is 3?

2) A running back in Europe lists his speed as 6.0 s for 31 m. How fast can he run 48 yds?

First, change 31 m -> yds. Now speed = distance/time. For time = distance/speed = [48 yds]/[(31m*1.0936 yd)/(6.0 s)]. Number of sig. figs. is 2?

3) A vehicle traveling at 57 mi per hr. has a fuel consumption of 18.6 mi per gal. If vechicle is carrying 5.3 gal of gasoline, how many min. does the driver have before vehicle runs out of fuel?

speed = 57 mi/hr; consumption = 18.6 mi/gal

18.6 mi/gal *5.3 gal = amt. of mi able to travel = distance, so time = distance/speed = (98.58 mi)/(57 mi/hr) = time in hr. -> convert to min ?

Number of sig. figs. is 2?

4) Diameter of C atom found in Pb of pencil is 0.15 nm. Suppose a line is drawn on piece of paper that has width of 0.330 mm, length of 52.000 mm, and thickness of 0.010 mm, determine number of atoms in that line.

First find Volume of line by l*w*h = mm^3, and covert to m^3 where 1 m^3 = (1000 mm)^3. Convert nm to m (0.15 nm*(1m/10^9 nm)). Now divide C atom's diameter by 2 for radius to use V = (4/3)*pi*r^3. Divide V of line/V of 1 C atom. Number of sig. figs. is 2?

Thank you.
 
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Physics news on Phys.org
Try this tutorial on significant digits.

http://ist-socrates.berkeley.edu/~chem1a/sigfigs/sigfig2.htm
 
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