Creating a ficticious force can make it easier to understand!
Can you imagine going up to a little kid and saying “Hey Johnny, you’re wrong, you’re not sucking on the straw, air pressure is pushing it up the straw”?
hey, we’ve been telling these lies for a very long time, and we will probably do so forever.
Wait a minute, what exactly is the cause of the ficticious “centrifical force” anyways? Is it Inertia?
I’m an engineer who works on helicopters. You may have noticed that they have lots of parts that spin. Sometimes the use of “centrifugal” force, and it’s companion, “coriolis” force makes a particular problem a little easier to understand. Sometimes it confuses the heck out of people. The “cause” of these forces is inertia. The key is selecting the frame of reference for your discussion, and being consistent.
If you want to look at something in a rotating reference frame, (as opposed to the “fixed” “Newtonian” inertial frame, as in the case here - where we’re talking about satellites) then you have to explain why objects move the way they do with respect to that moving frame. That’s where these ficticious forces come in.
Personally, I don’t like to call them ficticious myself, but I also don’t argue if someone else does.
From the site I cited before:
In other words, to a passenger riding in car it seems as if some mysterious force is causing the tennis ball to move sideways. This fictitious, non-existent force may be called “centrifugal force.”
Actually, to an outside observer, the ball is moving along its original straight-line path, in accordance with Newton’s first law. No sideways force is acting on it at all!
I was going to add “until it hits the side of the car,” but it would be more precise to say “until the side of the car hits the ball.”
My experience in teaching is that, more often than not, such explanations confuse people.
In physics, I try to consider a Newtonian (inertial) frame of reference whenever possible. Once a student thoroughly understands problems in this frame, it may be convenient to consider other (non-inertial) frames of reference.
Unfortunately, many people (especially laymen) jump right into non-inertial frames of reference, leading to erroneous ideas such as “a satellite is in orbit because of the cancelling forces of gravity and centrifugal force.”
I don’t see how this explanation makes things more clear, just wrong. A student given this explanation would thus think that a satellite is not being accelerated, while in fact it is.
For the explanation of straws, I also must disagree. It often seems as if I spend more time trying to “unteach” incorrect explanations, than explaining correct ones. If a child really wanted to understand how a straw worked, I would indeed say “outside air pressure is pushing your soda up the straw” and see how that exlanation sits with the child. Don’t sell kids short; they may be capable of understanding more than you think! 