Your "science catechism" idea that discourages rational thought is interesting. I must admit there's probably some truth to it.

> Now, as any butcher will tell you, a five pound
> steak is still a five pound steak when you
> throw it up in the air. The concept "weight" as
> held by the common man, is exactly what Newton
> meant by "mass".

The thrown steak, however (or thrown person) might claim that they became "weightless".

I was taught that weight = mg and doesn't change just because you jump out of an airplane or play in the water or ride an elevator. Astronauts feel weightless, but it is their weight(the force of gravity on them) that causes them to orbit the Earth. I tell my students the scale force changes, not W = mg. I tell them they can't really be weightless because they'll always be orbiting around something (the Earth, the Sun, the center of the galaxy).

A textbook we started using this semester, however, calls mg the force of gravity and allows for weight to be the response to the pressing of the floor. For this author you're weightless when you jump out of an airplane and your weight changes as you ride an elevator.

Perhaps the catechism is being changed. I seem to need to do some rational thinking about this.

• Weight as Force - doctordick - April 6, 2001 - 13:58 UTC
  • "Again" says the little one. - johnpowell - April 6, 2001 - 16:45 UTC
    • No real argument here! - doctordick - April 7, 2001 - 00:52 UTC