Archive for September 24th, 2014

September 24, 2014

No Freakin’ Way. Did that really just happen? To me?

by Janie Jones

So you must now all share in my Physics shock.

Today we had lab.  Lab so far has been mostly us looking confused and in pain trying to follow the mumbling ramblings of our teaching assistant (the TA) who is apparently too brilliant to be understood by any of the classmates I’ve talked to about what is going on in lab.

Today’s lab was on projectile motion.  I had been assigned a lab partner whose grasp of physics was no better than my own.  Somehow, perhaps due to the grey hair, I became the “leader,” and was responsible for most of the measurements and calculations and I pretty much thought we’d be screwed.  We had to calculate where to put a small cup on a stand on the floor in order to catch a ball which was released from a ramp which shot it off the table.  We were given the height of the opening of the basket and the diameter of the opening (which we were told wasn’t strictly necessary for the calculations).  We had to measure all the rest of our variables, calculate the speed and velocity of the ball, do the derivations for the equation to calculate the position for the basket, and then, once we had done the calculations we were given 5 tries to try and get the ball into the basket.

If the ball went in on the first try we’d automatically get full credit for the lab without having to do the homework for the week.

If the ball went in on the second try, we’d still have to do the homework and we’d only earn the points we earned from doing the homework.

If the ball took 3 tries, we’d have to do the homework, but with a 1 point penalty to our final homework grade.

If the ball took 4 tries, we’d have to do the homework with a 2 point penalty.

And if the ball took 5 or more tries, we’d have to do the homework with a 3 point penalty.

I was hoping against hope to break even and just not have to worry about a penalty, because I figured there was no way my partner and I would be able to sink that ball on the first try.  After all, I was the one leading this party and it involved math, my arch nemesis.

So, we measured the speed of the ball and I calculated the velocity of the ball.  I measured the height of the end of the ramp.  I asked for just a little help with deriving the equation to make sure I was going in the right direction.  I crunched the numbers.  I conferred with my partner, who said, “I trust your math more than mine.”  I shuddered, that did not bode well.

From there I followed the directions implicitly.  We used a plumb bob to find the horizontal position exactly below the ramp.  We shot the ball off the ramp onto carbon paper so it marked the floor where it hit, then we shot the ball from about a third of the way down the ramp onto the carbon paper to mark a second point.  I got out a meter stick and lined up the two carbon paper points and the point indicated by the plumb bomb exactly below the ramp.  Then I placed a target at the distance from the ramp that I got from my calculations, lining up the cross hairs with the line connecting my three points.  I verified this with my partner.  We agreed this was as good as it was going to get.  We agreed that it would take a miracle for this to work.  I said, as long as it goes in on the second try I’ll be tickled pink.

The TA brought over the cup on the stand and lined it up on our target.  My partner released the ball down the ramp.  I stood at the basket waiting to judge how far it was off so I’d be ready to adjust it accordingly.

And, then the damn thing sunk perfectly in the cup on the first damn try.


I’m stunned.

And thrilled I don’t have to do lab homework this week.