Wednesday, October 01, 2008

Physics or Current Events?

I gave my students the first intermediate exam this evening in PHYS 218. Here's the third problem:
(3) 20 points. A corrupt congressman – or do I repeat myself? – stands at the edge of the roof of a tall building and throws a bag of $7.0 × 10^11 of your tax money away. He throws the massive bag of loot exactly horizontally with a speed of 5.5 m/s. The bag is caught by a debt-maddened and real-estate-crazed investment banker who is standing on the street below, 27 m away from the side of the building. Calculate the height of the building. (Assume there is no air resistance.)

The answer, in case anyone's curious, is 120 meters (to two significant figures). And 7.0×10^11 is 700 billion -- a nauseatingly familiar number, at this point.


Jeff Pruitt said...

I loved those projectile motion problems! However, when I taught help sessions they always gave students the hardest time. I don't think they could ever grasp the concept of gravity only working in the vertical direction.

Just yesterday I decided to calculate how thick a stack of 700 billion bills would be.

It's 47,500 miles. That's over twice the distance of a geosynchronous orbit.

Perhaps we could use the money to build a space elevator - literally...

John Van Naarden said...

Please tell me this is the first in a long series of great exam questions.

Thanks for the laugh, Jim!

itsmecissy said...

EXACTLY why I never took physics (LOL).

I have enough to torture myself with.

lemming said...

hee hee hee

Mort Chien said...

Jim, I like it! I finally understand economics.

Mort Chien

Jim Wetzel said...


I thought about you more than once today. A group of seven of us from the day job took a day of pee-tee-oh and went over to Dayton in order to tour the A.F. Museum. We went on the "behind the scenes" tour and saw many restorations in progress. It was excellent.