Physics 121
9/3/10
Prof. E. F. Redish
1
1
•
Theme Music:
Paul Simon
When numbers get serious
•
Cartoon:
Bill Waterson
Calvin & Hobbes
9/3/10
Math is different in science
from in math class!
•
Math in physics is fundamentally about
relationships among measurements
,
not primarily about calculating – or even
solving (though we do some of that).
•
Functional dependence
is critical.
“More of this means more of that”
is not
good enough.
How much
more
matters.
9/3/10
7
An example from a math exam
•
Writing the equation
in this problem on a
physics exam would
receive 0 credit and
the comment: “This
is a meaningless
equation!”
The population density of trout
in a stream is
where
r
is measured in trout
per mile and x is measured
in miles.
x
runs from 0 to 10.
(a) Write an expression for the
total number of trout in the
stream. Do not compute it.
9/3/10
8
r
(
x
)
=
20
1
+
x
x
2
+
1
How would you fix this?

This ** preview** has intentionally

**sections.**

*blurred***to view the full version.**

*Sign up*