I use speed as "good" example of "bad" physics. Other clips that I like
to use are the boat jump scene from Live and Let Die (Range=120ft) and a
scene from Jackie Chan's rumble in the Bronx where Jackie jumps from the
roof of a parking ramp on to the balcony of an apartment across the
alley. The camera angle allows for some reasonable estimates of
horizontal and vertical distance. I also like the clip because there
are some lovely mountains in the background behind the parking garage
(in the Bronx?) There's also the cliff diving scene in Butch Cassidy,
but there's an unfortunate edit that makes it difficult to judge the
time of flight.
"An expert is a man who has made all the mistakes which can be made in a
very narrow field."
- Niels Bohr
-----Original Message-----
From: Forum for Physics Educators [mailto:PHYS-L@list1.ucc.nau.edu] On
Behalf Of Brian Blais
Sent: Thursday, February 10, 2005 8:33 AM
To: PHYS-L@LISTS.NAU.EDU
Subject: Analyzing movies: Speed, with Keanu Reeves
Hello,
I do a number of exercises in class where we analyze scenes from movies,
or advertisements in magazines, for their treatment of physical reality.
After doing a calculation for the a particular scene in the movie
"Speed", with Keanu Reeves, I was somewhat surprised. I was wondering
if anyone else has done this, and are there other good movie scenes
which you have used?
The scene in question is a jump across a gap in a bridge of 50 ft, by a
bus going about 70 miles an hour. Now, it is unclear in the movie if
there is a ramp, and how much of one there is (the scenes conflict
somewhat from one time to the next). Barring that, could a bus manage a
50 ft jump at 70 mph, and what would it take to do it? If you treat the
bus as a particle, :), one calculates a take-off angle of a little less
than 5 degrees necessary to get across, which doesn't seem like a whole
lot to me. I could even accept that I wouldn't recognize a 5 degree
ramp at the end of the bridge from the distances shown in the movie.
Now, I imagine that the worst part of this is the "particle" assumption.
Certainly any rotation of the bus would cause it to land on its side.
There may be friction losses that I am not accounting for also. Is
there anything else major that is missing here?
I made sure to tell my students not to do this at home. :)
In addition to "Speed", I also like going through an analysis of
Armageddon, where the physics is *really* bad. I was surprised,
however, that the "Speed" bus-jump was not *completely* ridiculous from
initial calculations, just not particularly plausible.