1.2.2 Unit Conversion and Dimensional Analysis Flashcards
Unit Conversion and Dimensional Analysis
- All physical quantities have units associated with them.
- The choice units you use for measurement is arbitrary. You can always convert to mks, which is the system preferred in physics.
- There is another useful aspect of units. They can be used to check and understand equations.
note
- Question: Could you figure out the value of the exponent of c?
- Answer: Yes, by using units or dimensional analysis.
After 2.3 seconds with an acceleration of 9.8 m/s^2, how far does an object travel?
(1/2)(9.8 m/s^2)(2.3 s)^2 = 26m
One inch (in) is equal to 2.54 centimeters (cm). How many centimeters are in 12.0 inches?
30.5 cm
Suppose the initial volume of a gas is 198 L, the work done by the gas is -2.0*10^4 J and the pressure is 1.0 atm. Which of the following is needed to find the final volume of the gas?
a conversion from J / atm to L
Suppose you are told that 15 quarts (qt) = 14.2 liters (L). What is the conversion factor you would use to convert from quarts to liters? What is the conversion factor you would you use to convert liters to quarts?
quarts to liters: 14.2 L / 15 qt
liters to quarts: 15 qt / 14.2 L
If a 1/4 pound hamburger weighs 113.4 grams, which of the following is a conversion factor for pounds (lb) to grams (g)? Also, how many grams are in 1.4 pounds?
The conversion factor is 113.4 g / (1/4 lb). There are 635.0 grams in 1.4 pounds.
Suppose you are told that 1 qt = 0.946 L. Which of the following statements is not correct?
(1 qt/0.946 L)(365) = 365 qt/L
Which of the following is the unit of specific heat capacity?
None of the above. (J/C*kg)
Which of the following statements related to conversion factors is false?
A conversion factor is the ratio of the given unit to the required unit.
Suppose a laboratory experiment lasted 4,532 seconds. Which of the following conversion factors would be used to figure out how many hours the experiment lasted?
Both A and B
