Question:Questions from a simple calculation with units.

Question:Questions from a simple calculation with units.

Hi,

I am new to Maple and doing a trivial calculation raised a few questions. I tried to calculate the average density of a wire with the following specs:

• diameter = .40 inches
• length = 1000 feet
• weight = 61 pounds

Here's what I have come up with.

`with(Units[Standard]):`
`wirediameter:=.40[inch]:`
`wirelength:=1000[ft]:`
`wirevolume:=(wirediameter/2)2 * Pi * wirelength:= `
`wireweight:=61[lb]:`
`wiredensity:=wireweight/wirevolume`

I get a result of: (3517.654557[kg/m3])/π. I then had to (Rt Click | Approximate | 5) and Replace units] from kg/mto g/cm3

Going through this process left me with a few questions:

1. Can I get Maple to approximate π to a few decimal places automatically or will any calculation involving π give me a result with the letter? Should I just use 3.1415 instead? For the purposes of this calculation, four decimal places is more than sufficient. To be honest, throwing the spool of wire into a pool would really give me the information I need :)
2. Can I get Maple to give me results in specific units without the need to (Rt Click | Units | Replace Units)? I tried to specify wiredensity[g/cm3] but that didn't give me the results I wanted.
3. Can I "preload" the Units package (is that the right term?) so that I don't have to manually call it every time I want to use units?

Many thanks,

Perry

This has been branched into the following page(s):
﻿