| Dr. Tim Gay
Announcer: Boeing presents another in a series
of essays from contemporary opinion leaders. Today, University
of Nebraska professor of physics, Dr. Tim Gay.
Dr. Gay: It’s third and goal from the
eight, with 50 seconds left to play in the game. Down by six
points, its crunch time for the home team. The quarterback takes
the snap and hands the ball off to our mercury-quick running
back for a dive play up the middle. He turns right finds his
alley, exploding toward the goal line. Just as he’s about
to take it in, he runs into a brick wall disguised as a middle
linebacker. With a vicious crack of the pads, our running back
is leveled.
Being a physics professor, I tend to look at these altercations
a bit differently than most fans. That hit was pretty violent.
But exactly how much force did our running back experience?
Newton’s Second Law is the basis of the branch of physics
called mechanics, and it tells us that force is equal to mass
times acceleration. Knowing our running back’s mass and
his acceleration (actually, a deceleration) during the hit allows
us to calculate the force he feels. He’s a big guy, weighing
in at 240 pounds. Just before contact, he was moving at top
speed, 30 feet per second. The duration of the blow is less
than a fifth of a second, but that’s all it takes to stop
him dead in his tracks. Putting this data together gives a surprising
result; our running back was stopped with a force of almost
two-thirds of a ton. No wonder they call football a contact
sport!
I give this kind of lesson on a regular basis to the 78,000
fans who attend Nebraska Huskers home football games in Memorial
Stadium. I do it because I love any and all aspects of the game
of football, but also because I think it’s important for
scientists to communicate to the public why science is interesting
and how it has an impact on everyday life. The public is interested
in science if it can be made relevant to something they care
about. And for the 78,000 students in my physics class, what
they care about is Husker football.
Announcer: Boeing. Forever New Frontiers.
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