Wednesday, February 27, 2013

Honors: Momentum/Rotational Motion/Gravity Study Guide

I was going to try to squeeze in a lab before the next unit...but then almost no one turned in Momentum III and those that did left most of it blank. I also found out that I'll be gone on Friday and I didn't want you doing a lab while I'm gone. So today (and tomorrow and Friday) are going to be work days. In addition to completing Momentum III like you were supposed to, you can work on the study guide for our second test, which will be Monday.

Study Guide









Posted by L. Volkening
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3 comments:

  1. UnknownMarch 1, 2013 at 9:48 AM

    How come number 9 is 4m/s

    ReplyDelete
    Replies
    1. L. VolkeningMarch 1, 2013 at 11:16 AM

      A railroad diesel engine has 4 times the mass of a flatcar. If a diesel engine coasts at 5 m/s into a flatcar that is initially at rest, how fast do the two coast after they hook together?

      So let's say the engine is 4 kg and the flatcar is 1 kg. That means the total momentum before the collision is:

      P = (4 kg)(5 m/s) + (1 kg)(0 m/s) = 20 N*s

      After they connect, the engine and flatcar together have a mass of 5kg, so

      20 N*s = (5kg)v

      Divide both sides by 5kg, and you get the velocity of the combined train as 4 m/s.

      Delete
  2. UnknownMarch 1, 2013 at 6:23 PM

    Ohhh I get it now. Thanks miss.

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