I understand that in order for an object to maintain circular motion, its velocity vector must be travelling perpendicular to its position vector and constantly changing inwards, hence an acceleration towards the center of the circle. I know that the acceleration towards the center is typically caused by other forces, like tension on a string, and that these are called centripetal forces I believe? However, objects in circular motion tend to want to be away from the center instead of towards. A bucket of water tied to a string and twirled around in a circle will result in the water staying in the bucket: if the water is exhibiting circular motion, would it not thusly be accelerating inward, and thus escaping the bucket? I’ve heard that it’s a difference of frame of reference, but even looking from out to in, I can’t see how the water would be accelerating inward and yet remain in the bucket without support. Would there not be some force pushing the water into the bucket? And yet, centrifugal force is considered a fictitious force. I don’t understand. I know I understand some level of physics but please explain it like I’m 5 because I can’t seem to actually understand this.
Imagine slamming on the gas in your car. The car lurches forward, pushing your seat into you, and you start to accelerate forward.
As the driver, though, you feel like you are being pushed back into your seat, though it’s pretty obvious that there is no force pushing you back, it’s just the inertia of your body trying to stay put.
The only force in that system is the force of the car accelerating you forward, and the feeling of being pushed backwards is a fictitious force.
It’s the exact same with rotational motion, just trickier to wrap your head around. If you have acceleration, you know there are unbalanced forces, and an object in orbit is constantly accelerating.
This.
Ficticious force doesn’t mean that it doesn’t act like a force. From the frame of reference of the car, it totally liiks like there’s a force pushing you into the car seat, and as a passenger in the car, there’s no way to judge from the acceleration alone whether the car accelerated or the Earth’s gravity field changed.
Or to put it differently: it feels identical to stand in a space ship accelerating upward at 1G and standing in the same space ship while it’s parked on the surface of Earth.