When bicycle and motorcycle riders pop a wheelie, alarge acceleration causes the bikes front wheel to leavethe ground. Let M be the total mass of the bike-plus-ridersystem; let x and y be the horizontal and vertical distanceof this systems cm from the rear wheels point of contactwith the ground (Fig. 10-72). (a) Determine the horizontalacceleration a required to barely lift the bikes front wheeloff of the ground. (b) To minimize the accelerationnecessary to pop a wheelie, should x be made as small oras large as possible? How about y l How should a riderposition his or her body on the bike in order to achievethese optimal values for x and y l (c) If x = 35 cm andy = 95 cm, find a.FIGURE 10-72 101.

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