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Re: [Phys-l] pseudo-force



??? The original question was WHAT IS a pseudo-force? From the responses so
far, it appears that the terms pseudo-force and non-inertial force are being
used interchangeably. Is that correct?

Bob at PC

-----Original Message-----
From: phys-l-bounces@carnot.physics.buffalo.edu [mailto:phys-l-
bounces@carnot.physics.buffalo.edu] On Behalf Of Ludwik Kowalski
Sent: Thursday, October 26, 2006 8:51 AM
To: Forum for Physics Educators
Subject: Re: [Phys-l] pseudo-force

I think that a centrifugal force F is real; it can be measured. Suppose
a ring is sliding along a rotating stick. We expect F=m*a, where a is
the ring acceleration, with respect to the stick, directed away from
the center. One can measure static F (with a calibrated spring mounted
on the stick) and one can measure the acceleration (when the ring is
allowed to slide). What is wrong with this point of view?

Ludwik Kowalski
Let the perfect not be the enemy of the good.

On Oct 26, 2006, at 7:23 AM, Anthony Lapinski wrote:

Pseudo forces are usually mentioned during circular motion. Everyone
knows
that when you turn your car sharply to the right, you move to the
left. So
you naturally think there is an outward "centrifugal" force on you. But
it's really just your inertia -- your tendency to want to move in a
straight line. There isn't an outward force (on you) because every
force
must have a source! So we call these outward forces "pseudo forces."
There
IS an outward force, but it does not act on the object in question
.It's
just the reaction force of the net inward (centripetal) force for an
object moving in a circle. Or spin a stopper. The inward (net) force is
the string on the stopper. The reaction force is the stopper on the
string. It is outward, but does NOT act on the stopper (as many people
believe).

This is a very difficult concept for my students, and for most people.

Hope this helps!

Forum for Physics Educators <phys-l@carnot.physics.buffalo.edu> writes:
Some questions:

What do people mean by the term "pseudo-force"?

Is a pseudo-force a force?

Why is it called a pseudo-force?

Is this concept crucial/useful/marginal/unhelpful?
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