PDA View Full Version : Ps question inaccensa08-15-2009, 10:56 AMI took the free MCAT test online from kaplan. i am a little about a particular question. If a cyclist changes from a smaller tire to a larger tire with the same internal pressure, how is the size of the contact path affected? Acc to kaplan, the contact path is unaffected, since the size of the tire depends solely on the pressure. I thought of this as P=F/A I thought the mass will be changed, since you are using a larger tire, assuming that the force will increase and the area will also increase, but the ratio will remain the same. So the area increases. I realize that my assumption that mass increases was wrong, but is that really thinking it incorrectly? pdehay08-15-2009, 03:32 PMhypothetical, i have two bikes, with bigger and smaller tires, i weigh 100 lbs(yikes) and my pressure is 100 psi that means at that pressure i need 1 inch of surface area total my contact area on both tires is still only total to 1 in sq same for each bike they ask these a lot, where you hold one variable constant, F is inherently constant (you dont change weight) and the pressure is constant, so youyr third (and last variable should be too)