# Interval notation and specifying units (v vs. t graph)

1. Aug 30, 2011

### Genecks

1. The problem statement, all variables and given/known data

#5 and #6 of the attached pdf on page 5 (graph on page 4 relates to said problems)

Note: The professor did not cover how to do a problem like this, and the book does not have a similar problem, nor any other handouts. This definitely was a unique question.

I'm unsure if I should list the units or not within the interval notation.
I can't find a single justification on the web whether or not do such.

2. Relevant equations

Should I be putting all of #5 and #6 in interval notation? How so?
What would be a proper way to word it?

3. The attempt at a solution

(45, 87.5)

[0, 45)U(87.5, 100]

Right?

Say that I want to express the time interval during which a particle is moving to the right.
Time is in seconds...

At 0 and between 45 seconds, the particle is moving to the right.
AND
Between 87.5 seconds and 100 seconds, the particle is moving to the right.

Or would I list [0 s, 45 s)U(87.5 s, 100 s]

Basically, this has to do with a physics problem.
Moving to the right means the particle is moving in a positive direction.
There are other times during which it moves in a negative direction (left); that occurs between 45 seconds and 87.5 seconds.
At t = 45s and t=87.5s, y=0

#### Attached Files:

• ###### 105hw1.pdf
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Last edited: Aug 30, 2011
2. Aug 30, 2011

### PeterO

I am happy with the way you gave your answers - or were you merely quoting the answers section of the file to show us what it should have been?

There is always 0 <= t < 45 especially if you can type one of those snappy "less than or equal to" signs. Very easy with a pen and paper.

3. Aug 30, 2011

### Genecks

Are you happy with the "s" unit measurement being involved with the interval notation?

No, I was not quoting. I don't have the answers.