Name:
Section:
Unit 1: Introduction—Post-lab
I.
Dimensional Analysis1
In the US, we specify how effectively a car uses gas (fuel efficiency) by citing how many miles per gallon
it gets (MPG). In Europe, they cite liters per 100 kilometers (LPK). Note the conversion factors:
 1 mi = 1.6 km
 1 gal = 3.8 liters
1. Does a more efficient car have a larger or smaller MPG number? Explain how you know.
2. Does a more efficient car have a larger or smaller LPK number? Explain how you know.
3. If M is the number of miles per gallon a car gets, and L is the number of liters it takes to go 100 km,
find a mathematical equation that lets you convert M to L.
II.
Measurement Error
A student measures the diameter of a small cylindrical object and gets the following readings:
4.32, 4.35, 4.31, 4.36, 4.37, 4.34 cm
(a) What is the average diameter from these readings?
(b) What is the standard deviation of these measurements?
1
Adapted from Maryland Thinking Problems, Maryland Physics Education Research Group.
Unit 1 Post-lab- 1