My son has several big tests coming up, so Saturday night’s
activity was to have a jovial study session.
Isn’t that what every family does for fun? The main entertainment value came from
recognizing how little this Mom and her Youngest Daughter knew about physics.
Most physics problems involve moving objects. The first problem we were given was
this: A plane flies 200 km due West from City A to City B. Then it flies 300 km 30 degrees north of west
from City B to City C. Along a straight-line
distance, how far is City A from City C?
My son said it would be much easier to solve if I drew a
picture. So I did, but I immediately
admitted defeat because the points did not form a right triangle. Instead I drew
a picture of people waiting in line at the airport, because waiting in line
does not involve moving objects, but stationary people, and therefore no
physics problem to solve.
As you can see, the solution does involve forming a right
triangle eventually. I will leave it to
you people who remember trigonometry to find the solution on your own.
Next question. If a body is moved from sea level to the top
of a mountain, what changes: its mass, its weight, or both?
After some discussion of what “body” means in
physics class (it means “an object” not “a dead human body”), we determined
that the weight changes, because the body is further away from the earth’s
center of gravity, but the mass does not change.
Then came the clincher.
He asked, “What metric units do we use to measure weight?
Daughter said, “Grams.” No, that
measures mass. She said, “Pounds.” Nope, that’s mass in the English system. Folks, you will never believe this, but the
answer is that weight is measured in newtons!
I thought the only thing measured that way was figs.
Next question. A stack of books is placed on a scale in an
elevator. The scale reads 165 newtons. The stack’s true weight is 165 newtons. Can you tell if the elevator is moving at a
constant velocity of 2 m/sec up, 2 m/sec down, or not moving?
Once I was able to stop thinking about bar cookies, I judged Youngest Daughter’s answer to be
correct: “Who would ever put a scale in
an elevator?” Clearly, this elevator is
in the physics department at a major university. My son told me later that no one
in his physics class questioned
the idea of placing a scale in an elevator.
We went on in this vein, until Youngest Daughter, who was
trying to stand on her head on the couch, said to her brother, “I have a
physics question for YOU. If I fall off
the couch at 3 meters per second, and I hit the ground in 13/10 of a second,
how long is the ground away?”
Son: “How LONG is the
ground AWAY? Three weeks? In California?”
But he set to work, saying, “It’s more complicated than you
think. Because, unbeknownst to you, you
Youngest Daughter: “I
After much calculating, he said, “This is a pretty big couch
– it’s 4.381 meters high.”
“So, did I break my neck?”
Then we moved on from Physics to English. He showed me a 55 page single-spaced typed
packet entitled “Concision” (meaning ‘leanness of words’). ’Nuff said.
Son: “Who was the
first man in space?”
Son: “No! There are two famous Armstrongs, and Louis
Armstrong is one of them.”
Me: “Lance Armstrong
is the other.”
Son: “Well, there are three
Son: “Right. Who was the first American in space?”
Son: “Where was the
Me: “Who is buried in
Son: “What are two
civil rights laws passed during the Eisenhower years?”
YD: “Thou shalt not
Son: “I don’t think
there are any American laws that begin with ‘Thou shalt not.’”
I doubt this study session left my son any better prepared
for his tests, but he did prove that I am NOT smarter than an 11th grader.