Ayasano
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- Messages
- 407
I feel that we've gotten down to just butting heads and each telling the other that reality works in a fundamentally different way, so I'm going to try and come at this from another angle.
As I said further back in the thread, centripetal and centrifugal forces aren't forces in and of themselves, they're classes of forces. In the examples we've been talking about with the car, gravity is the centripetal force, just like in the example of spinning around with a bucket, the force supplied by you pulling on the rope is the centripetal force. So, in the example of a car accelerating along a road with gravity holding it down, what is generating the centrifugal force? (We're assuming the car is not a lifting body and does not have wings) And why would such a balance of forces still result in a downward acceleration?
In my explanation, there is no upwards force beyond the reaction force from the road that stops the car sinking into the ground. The apparent weightlessness is simply a result of inertia. It's also worth mentioning that there is no force pushing you back into the seat as you accelerate, or sideways when you turn. The reason you feel like you're being pushed back or sideways is because the car is using its wheels to accelerate, which means that the acceleration is not directly affecting you. You're effectively "catching up" with the car. It's easy to observe this, just watch someone else drive while you're standing at a stationary point outside the car. (Which, really, is the crux of the confusion here. It's easier to understand what's going on from the outside)
So, please explain in full where all of the forces in your example come from.
(And FYI, I don't own a car. I walk everywhere or take public transport, as I live in the UK and everything is like a 5 minute walk from everything else)
As far as torque goes, I think you're simply misunderstanding how calculations and dimensionality work, there is no error in the textbooks. Length is required to make the math fit the observations, otherwise applying force at different distances from the pivot would produce the same torque, instead of more or less.
I understand what you're saying about motion following curved paths now, but you seem to have it backwards. In the absence of any forces, an object will stay at rest or travel in a straight line. A single force can only produce linear acceleration and curved motion. At least two forces are required to produce curved acceleration. In the case of the electromagnet, your hand is producing the second force because you're not keeping the magnet dead centre. If you were to use a stationary electromagnet and a moveable magnet, and slowly turn the electromagnet up, you would see the moveable magnet move in a straight line.
As I said further back in the thread, centripetal and centrifugal forces aren't forces in and of themselves, they're classes of forces. In the examples we've been talking about with the car, gravity is the centripetal force, just like in the example of spinning around with a bucket, the force supplied by you pulling on the rope is the centripetal force. So, in the example of a car accelerating along a road with gravity holding it down, what is generating the centrifugal force? (We're assuming the car is not a lifting body and does not have wings) And why would such a balance of forces still result in a downward acceleration?
In my explanation, there is no upwards force beyond the reaction force from the road that stops the car sinking into the ground. The apparent weightlessness is simply a result of inertia. It's also worth mentioning that there is no force pushing you back into the seat as you accelerate, or sideways when you turn. The reason you feel like you're being pushed back or sideways is because the car is using its wheels to accelerate, which means that the acceleration is not directly affecting you. You're effectively "catching up" with the car. It's easy to observe this, just watch someone else drive while you're standing at a stationary point outside the car. (Which, really, is the crux of the confusion here. It's easier to understand what's going on from the outside)
So, please explain in full where all of the forces in your example come from.
(And FYI, I don't own a car. I walk everywhere or take public transport, as I live in the UK and everything is like a 5 minute walk from everything else)
As far as torque goes, I think you're simply misunderstanding how calculations and dimensionality work, there is no error in the textbooks. Length is required to make the math fit the observations, otherwise applying force at different distances from the pivot would produce the same torque, instead of more or less.
I understand what you're saying about motion following curved paths now, but you seem to have it backwards. In the absence of any forces, an object will stay at rest or travel in a straight line. A single force can only produce linear acceleration and curved motion. At least two forces are required to produce curved acceleration. In the case of the electromagnet, your hand is producing the second force because you're not keeping the magnet dead centre. If you were to use a stationary electromagnet and a moveable magnet, and slowly turn the electromagnet up, you would see the moveable magnet move in a straight line.