Idontknowhatimdoing said:
This makes sense, but the fact that the normal force can be a reaction to a fictitious force just doesn't sit right with me. Does this mean that you don't need a real force for normal force to respond?
Think of spinning a ball around on the end of a bit of string. What happens if you let go of the string? (Newton's First Law)
The string is providing a
centripetal force to pull the ball on the end around the corner at every instance. You, the string holder, are providing that force though the string. Forget centrifugal farce. Oops. A real typo, but I am leaving it in place ;-)
If you use a very heavy ball, say 50kg and try to spin it around fast in circles around your head with a thin string, the string will probably break as it can't be pulled hard enough by you before it breaks.
Now let's look a physical loop runways.
Imagine a small steel ball, say 5cm in diameter, that you fire around the inside of a strong metal loop and at a speed high enough to ensure a number of loops, five or ten. Also imagine a thin paper loop where you fire a table tennis ball around, and it successfully performs several loops. Your loops are converting the balls' KE into centripetal force, until the KE drops to too low a value and enough energy simply can't be extracted..
Now imagine you use the steel ball and fire it around your thin paper loop at the same initial velocity as before - the steel ball will burst through your thin paper loop. The paper can't hold back against the momentum and convert enough of the steel ball's kinetic energy into a centripetal force and force it round the track. And as we know, if we fire the steel ball round the metal loop with insufficient energy, it might only manage one loop or even half a loop, then fall back. You can think of these solid physical loops extracting KE from the ball and converting that into the centripetal force. The loop is not reacting to an imaginary force, the loop is converting some of the KE into a real force.
Your science teacher can probably set up an experiment with markers on the strong loop and a timer visible, video the loops, and show that the speed decays faster than if you rolled the same ball at the same initial speed along a long metal surface, to show that the energy loss is greater than that due to friction and the ball doesn't travel as far when looping (you can use the radius of your metal loop to get the distance travelled). That excess energy loss is your centripetal force. You'd use a ramp of a height about say 50% higher than the loop diameter in each experiment to fire the ball into the loop, high enough that at a loop is guarenteed of course, and that the ball has the same KE at the instance it starts to go round the loop as when you use the ramp to roll it along the metal surface.
Hope I've phrased this correctly, if not I am sure some will correct things for me. (I'm currently unwell and mistakes might slip in. I've re-read it several times and corrected several already but just now my brain hurts.)