Projects 02 - RHR, Trebuchet, Magnets-in-pipes


Let's try a *gentle* competition.... First group to get these done correctly gets a prize!

(4i + 3j - 2k) x (-i - 3j + k)




Now find the MAGNITUDE of the resulting vector



4i x - i = 0
4i x -3j = -12k
4i x k = -4j
3j x -i = 3k
3j x - 3j = 0
3j x k = 3i
-2k x -i = 2j
-2k x - 3j = -6i
-2k x k = 0


Now find the MAGNITUDE of the resulting vector (OUCH!)

Add up the i's first:

  • 3i + -6i = -3i

Add up the j's next:

  • -4j + 2j = -2j

Now add up them thar k's

  • 3k - 12k = -9k

sooooooooooooooooooo our vector is:

-3i + -2j - 9k

And just like in planar (2x) geometry we calculate the magnitude of the resulting vector by squaring everything, adding 'em up and rooting the result:

(-32 + -22 + -92)1/2


= 9.70 or 9 if we were tracking siggie figgies

Comming before the end of the year:

  • A quick rhr quizzypoo like today's opening question (please make sure to give me your old test if I don't have it). A chance to gain back up to 4 points on your induction test


  • The First Annual GHHS Cross Product Challenge:


I know we want to do a professionally appropriate challenge to Johnson's classes, but I also wanted to make sure that we didn't have TOO much of a head start on them...


So... here's the information that we'll want to *OFFICIALLY* transmit to the JV today:

  1. The challenge will take place on the turf field on either the senior's last day or their 2nd to the last day
  2. The 'body' of the trebuchet must be 4' x 4' x 4' or less
  3. The lever arm can be any length and any material
  4. The counterweight can be any material and any mass
  5. The projectile will be a regulation fast-pitch ball
  6. Total cost of materials MUST NOT EXCEED $30 (reasonable material from home is acceptable)

Mr J and I are working to schedule a "Field Trip" for that day during 2nd/3rd/4th periods... TBD


Work o' the day:

The final *other* project we have for the duration is to design and carry out SOME sort of investigation involving neodymium magnets falling through pipes...

I purchased a number of 1/2" x 1/2" neodymium magnets to facilitate your work...please be GENTLE with them

Let's go with true inquiry on this one folks... pick some aspect of a magnet moving through a pipe and work to investigate that scientifically.

You will have:

1) Several different types of pipe

2) A number of 1/2" x 1/2" neodymium magnets

3) Other magnets as available

4) Vernier Labquest data collection devices with magnetic field probes

5) Multi-meters (please be careful)


Take a few moments to work on determining your investigative question to guide your lab.

This lab will be written up using our basic Baylor lab guidelines and is due