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Mechanics}Centripetal Force


\vec{F}_air acts in the direction as shown and the centripetal acceleration acts in the direction of \vec{F}_A. Centripetal acceleration is a net force, however, and thus,

f_x is in the positive direction and f_y is in the negative direction. Thus the force of the road is \vec{F}_B.

See below for user comments and alternate solutions! See below for user comments and alternate solutions!
Alternate Solutions
99percent
2008-11-06 06:20:59
Centripetal force is in the direction \vec{F_A}

Tires exert a force in the backward direction so that the car moves in the forward direction - By Newton's third law (Action-Reaction) - The road exerts an equal force in the forward direction, i.e., \vec{F_C}

the resultant of \vec{F_A} and \vec{F_C} will be in the direction \vec{F_B}

Bingo..!!
Alternate Solution - Unverified
Comments
tsharky87
2009-11-04 23:40:25
It seems to me that if we assume the car is back-wheel driven, then the force of the road on the back tires will be \vec{F_C}, and the force of the road on the front tires (which must be turned to the right) would be \vec{F_A}. So the driving tires are what makes it go forward and the turning tires are what pulls it toward the center, which makes sense. The resulting force of these is obviously \vec{F_B}.

But if we assume the car is front-wheel drive, then the back wheels are doing nothing but holding up the car, and the front wheels are the only force. Since the wheels must be turned to the right, the road is pushing the front wheels along where they are directed, \vec{F_B}.

I don't like this problem much and I got it wrong but that's just some insight that occurred to me.
NEC
Albert
2009-10-21 15:12:32
Thank you Yosun, for this wonderful site, I am learning a great deal!NEC
99percent
2008-11-06 06:20:59
Centripetal force is in the direction \vec{F_A}

Tires exert a force in the backward direction so that the car moves in the forward direction - By Newton's third law (Action-Reaction) - The road exerts an equal force in the forward direction, i.e., \vec{F_C}

the resultant of \vec{F_A} and \vec{F_C} will be in the direction \vec{F_B}

Bingo..!!
jmason86
2009-09-30 17:09:55
You said "The road exerts an equal force in the forward direction Fc".
The problem asks for "the horizontal force of the road on the car's tires."

It seems like by this logic, you should just go with (C). This isn't the right answer though...
Alternate Solution - Unverified
isina
2008-10-16 14:45:53
I do not completely agree with the answer on the grounds that it is not the only solution. Even if there is no wind force there is still force in +x direction. The reason that there is forward friction force is as follows: as the car moves in +x direction, its tires rotate in the reverse direction (at the point of contact their velocity vector points -x). So the friction of the road on the tires is actually to the opposite direction of the cars tires movement and on the same direction as the movement of the car. This results in a +x directed friction (hence the car moves).NEC
evanb
2008-06-30 11:50:46
Just a small typo: you need braces for F_{air} so that it doesn't look like F_airTypo Alert!
yosun
2005-11-10 02:00:50
BWHB: thanks for the typo-alert; it has been corrected. NEC
BWHB
2005-11-10 01:38:49
All the work is right but the answer is wrong. It's FB. NEC

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