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Mathematics Goes to the Movies

by Burkard Polster and Marty Ross

**Thirteen Conversations
About One Thing (2001)**

14:53

PROFESSOR: A car is traveling at 30 miles per hour when he sees the pedestrian
150 feet ahead. Using this equation we find that reducing the velocity to zero
requires a constant deceleration of 6.45 feet per second squared.

STUDENT: Don’t you have to assume that the car’s velocity remains
constant during the deceleration period?

PROFESSOR: Yes, you are right. The constant in this case is an average. A better
example of nearly constant deceleration is constant freefall of a body near
the Earth’s surface, a pair of glasses dropped from a building, for example.
Any more questions before we move on?

1:18:11

PROFESSOR: We can determine the range R with this equation. An object projected
horizontally will reach the ground at the same moment as a free-falling one
dropped from the same height.

STUDENT (Mr Hammond): Even if one of them is significantly…

PROFESSOR: There are no “ifs”. Physics is an exact science. The
laws of the universe are absolute.

PROFESSOR: I see Mr. Hammond is late again, hmm.

STUDENT: There was a party last night. He fell from the top of the math building onto the quad.

OTHER STUDENT: No, he didn’t. The range is too great. If he had fallen, he would have landed near the bushes. He must have jumped, wouldn’t that be right, Professor?