Maximus 190
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I’m stuck on an Isaac physics question, I’ve tried this a couple times and keep getting the same answer. Attachment 879902

My working out is here, Attachment 879904

Also I have watched the hint video and they got a different equation when equating the vertical forces. I have Ncos(30) + mu*Nsin(30) = mg, but they have -mu *Nsin(30). On the diagram they have also drawn the friction force down the slope, but surely it should be up the slope? Super confused. Would appreciate help.

Also here is an image of the hint with a diagram and their starting equations. Attachment 879906
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ThiagoBrigido
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(Original post by Maximus 190)
I’m stuck on an Isaac physics question, I’ve tried this a couple times and keep getting the same answer. Attachment 879902

My working out is here, Attachment 879904

Also I have watched the hint video and they got a different equation when equating the vertical forces. I have Ncos(30) + mu*Nsin(30) = mg, but they have -mu *Nsin(30). On the diagram they have also drawn the friction force down the slope, but surely it should be up the slope? Super confused. Would appreciate help.

Also here is an image of the hint with a diagram and their starting equations. Attachment 879906
There is nothing attached.
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ghostwalker
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(Original post by Maximus 190)
...
TSR has problems with attachements sometimes - try uploading to your favourite image hosting site and linking across.
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Maximus 190
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(Original post by ghostwalker)
TSR has problems with attachements sometimes - try uploading to your favourite image hosting site and linking across.

https://imgur.com/a/i78v1ZY
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ghostwalker
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Question asks for the maximum speed. I.e. if it went any faster the car would not make it round the curve. So friction is acting, in general, towards the centre of rotation, and hence down the slope.
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Maximus 190
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(Original post by ghostwalker)
Question asks for the maximum speed. I.e. if it went any faster the car would not make it round the curve. So friction is acting, in general, towards the centre of rotation, and hence down the slope.
Oh right okay, I’ll try it again in a little bit. Thanks
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Maximus 190
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(Original post by ghostwalker)
Question asks for the maximum speed. I.e. if it went any faster the car would not make it round the curve. So friction is acting, in general, towards the centre of rotation, and hence down the slope.
Tried that, now I’m just getting the same final equation but negative mu * sin 30 on the bottom. This gives me a negative value for the velocity squared?
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Maximus 190
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(Original post by Maximus 190)
Tried that, now I’m just getting the same final equation but negative mu * sin 30 on the bottom. This gives me a negative value for the velocity squared?
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ghostwalker
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(Original post by Maximus 190)
Tried that, now I’m just getting the same final equation but negative mu * sin 30 on the bottom. This gives me a negative value for the velocity squared?
At a guess you only changed one of your intial equations, but I've no idea as you haven't posted any working!
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Maximus 190
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(Original post by ghostwalker)
At a guess you only changed one of your intial equations, but I've no idea as you haven't posted any working!
Do you see my working out now? I can upload to another site and link if not. I have the sane equations as the hint video now
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ghostwalker
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(Original post by Maximus 190)
Do you see my working out now? I can upload to another site and link if not. I have the sane equations as the hint video now
Can see it now. cos30-mu sin 30 is still postive, giving a positive v^2. Does it not?
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Maximus 190
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(Original post by ghostwalker)
Can see it now. cos30-mu sin 30 is still postive, giving a positive v^2. Does it not?
Ohhh I’m in radians, one second ffs lol
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Maximus 190
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(Original post by ghostwalker)
Can see it now. cos30-mu sin 30 is still postive, giving a positive v^2. Does it not?
Yeah that worked, thanks!
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ghostwalker
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(Original post by Maximus 190)
Ohhh I’m in radians.
Classic! One thing to watch out for in exams, where you might have some questions in degrees and others in radians.
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