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App Mat 1998 Newtons laws

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15-06-2007 5:39pm

#1

Shox

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Join Date: February 2007

Posts: 60

Anyone help, im stumped??

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#2 15-06-2007 5:53pm
JC 2K3

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Don't bother with it, as Oliver Murphy(guy who wrote the App Maths book) said:

Ugh!Very tricky question because the friction exerted by A on B has an equal but opposite anti-friction which propels A forward!Should never have been asked.It’s a university question.

http://www.discoveringmaths.com/news/belvedere/

I never bothered to solve it at the time. It's not going to come up.

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#3 15-06-2007 6:35pm
ZorbaTehZ

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Join Date: August 2006

Posts: 2046

Solution

U(BG) Coeffecient of friction between B and ground
U(AB) Coeffecient of friction between A and B

P Force pulling B forward
S Normal Reaction of B

R Normal reaction of A
a acceleration

Equations:
P - [U(BG)].S = 55a
S = R + 35g
R = 20g

If A does not slip, then [U(AB)].R = 20a

SIMULTANEOUS!

P = 35.75g N

EDIT: Typo.

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