Environmental Engineering Reference
In-Depth Information
In this problem, the numbers are already in their simplest form.
5. Solve the math.
6. Rewrite the answer including the units.
or simplified:
Helpful Hints
In the 13 years of the AP Environmental Science exam, no one has ever lost points for failing to include
the units. However, it is
highly recommended
that units are included at every step to ensure that you're
solving the problem correctly.
When solving the problem, be sure to fully document all of your work, including the dimensional ana-
lysis in the topic that will be scored. If the problem is solved in the test pages for making notes and the
only answer is in the scored booklet, you won't receive any points, even if the answer is correct. In addi-
tion, often in the data-based question, partial points are given for showing the setup of the equation.
Scientific notation can be used.
Now answer the second question in the example:
1. Read the question to determine the final units.
The final units are coal cars per day.
2. Set the final units at the end of a dimensional analysis equation.
3. Check that the problem is set up so that starting units are converted into ending units.
4. Simplify the math, cancel out zeros, and simplify the numbers.
5. Solve the math.
6. Rewrite the answer including the units.
Now try the final question in the example.
1. Read the question to determine the final units.
The final units are trains per day.
