Another Real World Physics Lesson for "Truthers"

It’s time to give “truthers” another lesson in real world physics.

“Truthers” often insist that it is impossible to move more with less.  Yet, things like levers, pulleys, etc. allow one to do exactly that.   That tire jack that’s light enough for you to lift out of the trunk quite easily can lift up your car, no problem, something a person can’t do.   I weigh considerably less then my car, yet I can push it, no problem.  The fact that the car has wheels does not change the fact that it’s more massive than I am.

Now, since “truthers” are going to want me explain how the mass of the upper floors were able to move the much larger mass of the lower ones, it’s a little thing called force.

According to Newton’s 2nd Law of motion force is mass times acceleration, which is written as F = ma (source).  Mass does not move mass, force does.   Now, obviously, the collapsing upper floors had both mass and acceleration, and therefore force. The thing is, until the upper floors made contact with the lower ones, the lower floors had mass, but weren’t moving- YOU CAN’T HAVE ACCELERATION WITHOUT MOTION. If force equals mass times acceleration, and the lower floors aren’t moving, then, clearly there’s no force. Now, when the upper floors hit the lower floors, the lower floors would of course exert equal force on the upper floors, per Newton’s 3rd Law of motion.

The thing is there’s one other force the collapsing Twin Towers had to contend with- the force of gravity. That’s right, gravity is a force. How do I know that?  It’s really quite simple.  If I drop a 65 gram tennis ball, we have mass (the 65 grams) and gravity accelerates the tennis ball at a rate of 9.8 m/s(2).  Since we have both mass and acceleration, gravity clearly fits the definition of force.

Now, as for the speed of gravity, “truthers” tend to missapply it in the case of the WTC collapse. In the case of the Twin Towers, it’s more accurate to use ACCELERATION DUE TO GRAVITY, which is 9.8 m/s(2) for the earth. Oh, and just for the record, acceleration is NOT the same as velocity.  As we see from the definition given here, “acceleration is defined as the ratio of change in velocity to the time interval over which the change occurs.” Hint: this means acceleration is NOT the same as velocity, although they are related.

On a different, but similar note, speed and velocity are NOT the same either. For example, say you’re driving down the freeway with a friend and your friend asks how fast you’re going. If you say you’re going 70 MPH, that’s speed. If you say you’re going 70 MPH due north, that’s velocity. Simply put, speed doesn’t have a direction, velocity does- any physics book will tell you that.

Finally, since “truthers” have trouble keeping these straight, force, potential energy, and load capacity are NOT the same thing.  

First, as we see from the quote here, load capacity is defined as “The weight that a building’s floors can support, generally measured per square foot.”

This quote gives the following definition of potential energy:

Potential energy, or stored energy, is the ability of a system to do work due to its position or internal structure. For example, gravitational potential energy is a stored energy determined by an object’s position in a gravitational field while elastic potential energy is the energy stored in a spring.

To put this in layman’s terms, if I take a tennis ball and hold it in my hand 3 feet off the ground, that’s potential energy; an object must be stationary to have potential energy.

Last but not least, as I pointed out at the beginning of this article, force equals mass times acceleration, which means in order to have force, one must have motion.

In short, when it comes to physics, members of the 9-11 “Truth” Movement have been watching far too many Roadrunner cartoons.

Also see: Real Physics vs. Wile. E. Coyote Physics

               

Advertisements

Posted April 21, 2008 by Victor Chabala in Real 9/11 Facts

%d bloggers like this: