Fundamental Applied Maths: Solution to a Circ. Motion Q

Cathalog

To anyone studying circ motion for the exam (I believe there are very few?) - can someone help me out with a question from the Fundamental Applied Maths Book?

11C - Q 4 in the new book:

A book rests on a horizontal shelf in the back window of a car. The coefficient of friction between the book and the shelf is 1/2. The driver of the car takes a bend at 6m/s. find (to the nearest metre) the radius of the tightest horizontal bend which the car can take without the book slipping.

I think what I'm doing wrong is applying the force of the centripetal force of the car to the book.
I end up with 2 equations but about 4 variables (m or car, m of book, coefficient of friction between car and ground, radius)

Thanks!

Cathalog

Cathalog wrote: »

To anyone studying circ motion for the exam (I believe there are very few?) - can someone help me out with a question from the Fundamental Applied Maths Book?

11C - Q 4 in the new book:

A book rests on a horizontal shelf in the back window of a car. The coefficient of friction between the book and the shelf is 1/2. The driver of the car takes a bend at 6m/s. find (to the nearest metre) the radius of the tightest horizontal bend which the car can take without the book slipping.

I think what I'm doing wrong is applying the force of the centripetal force of the car to the book.
I end up with 2 equations but about 4 variables (m or car, m of book, coefficient of friction between car and ground, radius)

Thanks!

And now I spot the Applied maths thread... Sorry for wasting valuable forum space..

finality

I'll revise this later and then see if I can help, if someone hasn't beaten me to it.

Do you have the answer to it?

Cathalog

finality wrote: »

I'll revise this later and then see if I can help, if someone hasn't beaten me to it.

Do you have the answer to it?

Cheers! Yup.

6 metres

finality

You can basically ignore everything to do with the car here, it's irrelevant, just look at the centripetal force on the book itself.

Found the question in my own book (the brown one) and that's the answer at the back, I was wondering why I wasn't getting 6 for ages until I checked it there :L

Cathalog

finality wrote: »

You can basically ignore everything to do with the car here, it's irrelevant, just look at the centripetal force on the book itself.

Found the question in my own book (the brown one) and that's the answer at the back, I was wondering why I wasn't getting 6 for ages until I checked it there :L

Ah I see. I got the same answer!

I double-checked my book there and it definitely says 6. It was killing me hah!

Sorry for wasting your time answering that q, but now at least...

a) My mind is put at ease
and
b) it was nice to see how someone else would lay out their answer!

finality

Cathalog wrote: »

b) it was nice to see how someone else would lay out their answer!

Hah in an exam layout goes out the window for me, I'm all over the place! (or even in general if I'm not making it nice for the internet )

Cathalog

Oh, haha. Same as me :P I feel sorry for the poor examiner who gets mine!