\(\overset{\underset{\mathrm{def}}{}}{=} \), Unit Conversions Example: A Short Drive Home, \(\mathrm{average \; speed} = \cfrac{10.0\;\mathrm{km}}{20.0\;\mathrm{min}}.\), \( = 0.500 \cfrac{\mathrm{km}}{\mathrm{min}}.\), \(\mathrm{average \; speed} = 0.500\;\cfrac{\mathrm{km}}{\mathrm{min}} × \cfrac{60\;\mathrm{min}}{1 \mathrm{h}}\), \( = 30.0\;\cfrac{\mathrm{km}}{\mathrm{h}}.\), \(\cfrac{\mathrm{km}}{\mathrm{min}} × \cfrac{1\;\mathrm{hr}}{60\;\mathrm{min}} \), \(= \cfrac{1}{60}\cfrac{\mathrm{km\;.hr}}{\mathrm{min}^2},\), \(30.0\cfrac{\mathrm{km}}{\mathrm{h}} × \cfrac{1\;\mathrm{h}}{3,600\;\mathrm{s}} × \cfrac{1,000\;\mathrm{m}}{1\;\mathrm{km}},\), http://cnx.org/contents/031da8d3-b525-429c-80cf-6c8ed997733a@9.74. Physics » The Nature of Physics » Physical Quantities and Units, Suppose that you drive the 10.0 km from your university to home in 20.0 min. Some hummingbirds beat their wings more than 50 times per second. Have questions or comments? Identify the metric prefix that corresponds to this factor of 10. In equation form, $$Average\; speed = \frac{Distance}{Time} \ldotp \nonumber $$, Substitute the given values for distance and time: $$Average\; speed = \frac{10\; mi}{20\; min} = 0.50\; \frac{mi}{min} \ldotp \nonumber $$, Convert miles per minute to meters per second by multiplying by the conversion factor that cancels miles and leave meters, and also by the conversion factor that cancels minutes and leave seconds: $$0.50\; \frac{\cancel{mile}}{\cancel{min}} \times \frac{1609\; m}{1\; \cancel{mile}} \times \frac{\cancel{1\; min}}{60\; s} = \frac{(0.50)(1609)}{60}\; m/s = 13\; m/s \ldotp \nonumber$$. However, other pieces of software that used these values for course corrections expected them to be recorded in the SI units of newton-seconds (N • s), as dictated in the software interface protocols. For example, there are 12 in. Because the wings beat so fast, the scientist will probably need to measure in milliseconds, or \(10^{-3}\) seconds. km/h to m/s – unit conversion from kilometer/hour to meter/second Km/h to m/s or km/hr to m/s conversion: To convert km/hr value to m/s value just multiply the km/hr value with 5/18 and get the value in m/s. The answer does seem reasonable. Missed the LibreFest? So for a quick approximation, halve the original number twice, then add #10# %. This is a lesson from the tutorial, The Nature of Physics and you are encouraged to log in or register, so that you can track your progress. Then we can get the average speed into the desired units by picking the correct conversion factor and multiplying by it.

Why? ›› Quick conversion chart of km/h to m/s. \(\mathrm{Average\;speed} = \)\(30.0\cfrac{\mathrm{km}}{\mathrm{h}} × \cfrac{1\;\mathrm{h}}{3,600\;\mathrm{s}} × \cfrac{1,000\;\mathrm{m}}{1\;\mathrm{km}},\), \(\mathrm{Average\;speed} = 8.33\;\cfrac{\mathrm{m}}{\mathrm{s}}\). The correct conversion factors are those that cancel the unwanted units and leave the desired units in their place.

In this case, we want to convert miles to meters, so we need to know the fact that there are 1609 m in 1 mi. (2) Multiplying by these yields 1 km/h to m/s = 0.27778 m/s. The problem asked us to solve for average speed in units of km/h and we have indeed obtained these units. This modified article is licensed under a CC BY-NC-SA 4.0 license. You may have noted that the answers in the worked example just covered were given to three digits. The idea is still to multiply by the conversion factors in such a way that they cancel the units we want to get rid of and introduce the units we want to keep. [ "article:topic", "authorname:openstax", "conversion factor", "license:ccby", "showtoc:no", "program:openstax" ], Creative Commons Attribution License (by 4.0). For a better experience, please enable JavaScript in your browser before proceeding. After the cancelations just described, we see the only units we have left are “kg” in the numerator and three factors of “m” in the denominator (that is, one factor of “m” cubed, or “m. (1) Start with the answer to (a) and convert km/h to m/s. in 1 ft, 1609 m in 1 mi, 100 cm in 1 m, 60 s in 1 min, and so on. In this case, we want to convert miles to meters, so we need to know the fact that there are 1609 m in 1 mi. 100 km/h = 100 * 1000 m/3600 s =.... You just replace the km with 1000m, and the hour with 3600 s. This method always works and soon you don't even have to think about it. We see the “miles” in the numerator in 0.50 mi/min cancels the “mile” in the denominator in the first conversion factor. We need to convert grams to kilograms and cubic centimeters to cubic meters. So to convert from km/h to m/s, divide by #3.6# Note that dividing by #3.6# is the same as dividing by #4# then adding #11.bar(1)# %. Be sure to cancel the units in the unit conversion correctly. How many km/h in 1 m/s? Your answer will appear in the m/s field.

What does this tell you about the different units in the SI metric system? Convert this to kg/m3. Given that 1 lb (pound) is 4.45 N, were the numbers being output by SM_FORCES too big or too small? Also, the “min” in the denominator in 0.50 mi/min cancels the “min” in the numerator in the second conversion factor. Think about how the unit is defined and state its relationship to SI units. The correct conversion factors are those that cancel the unwanted units and leave the desired units in their place. First we calculate the average speed using the given units, then we can get the average speed into the desired units by picking the correct conversion factors and multiplying by them. (Take this definition as a given for now—average speed and other motion concepts will be covered in later lessons.) 1 km/h is equal to 0.27777777777778 meter/second. By Steven Holzner . Let’s consider a simple example of how to convert units.

The problem asked us to solve for average speed in units of meters per second and, after the cancelations, the only units left are a meter (m) in the numerator and a second (s) in the denominator, so we have indeed obtained these units. Note that rounding errors may occur, so always check the results.

Do not delete this text first. It is often necessary to convert from one unit to another. Note that rounding errors may occur, so always check the results. We also want to convert minutes to seconds, so we use the conversion of 60 s in 1 min. … We see that the gram (“g”) in the numerator in 7.86 g/cm, Check that the units of the final answer are the desired units. Calculate average speed. Type in your own numbers in the form to convert the units! Unless specified, this website is not in any way affiliated with any of the institutions featured. We also want to convert minutes to seconds, so we use the conversion of 60 s in 1 min. Suppose we want to convert 80 m to kilometers.

A bus traveling at +29 km/h accelerates at a constant +3.7 m/s2 for 6.3 s. Register or login to receive notifications when there's a reply to your comment or update on this information. For example, you may measure the number of feet your toy car goes in three minutes and thus be able to calculate the speed of the car in feet per minute, but that’s not a standard unit of measure, so you need to convert feet per minute to miles per hour, or meters per second. Refer to Appendix B for a more complete list of conversion factors. Physics problems frequently ask you to convert between different units of measurement.

The answer 30.0 km/hr does indeed have three significant figures, so this is appropriate. Note: Average speed is distance traveled divided by time of travel. - A batmobile is moving with a constant velocity toward the north. \(\mathrm{average \; speed} = \cfrac{10.0\;\mathrm{km}}{20.0\;\mathrm{min}}.\)\( = 0.500 \cfrac{\mathrm{km}}{\mathrm{min}}.\).