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# M3 Trivial question about Banking watch

1. So there is a car going around on a bank. If you want to do stuff, you have to resolve to find R:

I have in my notes to make sure to ALWAYS resolve vertically and never perpendicular to the slope in this case. So:

So can someone just explain why this is the case? I don't want to just learn it without understanding.

Thanks
2. (Original post by 2710)
So there is a car going around on a bank. If you want to do stuff, you have to resolve to find R:

I have in my notes to make sure to ALWAYS resolve vertically and never perpendicular to the slope in this case. So:

So can someone just explain why this is the case? I don't want to just learn it without understanding.

Thanks
Because this is circular motion, the horizontal components of R and Fr are providing the centripetal force. This means that the vertical component of R is countering the vertical component of Fr and mg.

In normal statics questions, the component of mg perpendicular to the slope is equal to R, but in banked circular motion, R > perpendicular component of mg, so you can't work it out that way any more.
3. Because you model the car as moving around the inside of an upside down cone not a inclined plane.
4. i know this a stupid question...but i was doing m3 the other day..they mention slipping..but not whether up or down..so do i assume its slipping down?
5. (Original post by azzkikr616)
i know this a stupid question...but i was doing m3 the other day..they mention slipping..but not whether up or down..so do i assume its slipping down?
If you could post the whole question i might be able to help..

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