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Physics, 14.03.2020 05:27 rdrboo

The rider starts from rest at location at the edge of the in-ramp and goes down the transition. Typically, as the rider approaches the flat at location he will crouch down to get his center of mass as low as possible and thus increase his speed. To simplify the problem, let us initially assume that the rider stays upright as he goes down so that his center of mass location relative to his feet does not change from what it was at location . In the following problems, you can use the foot as the unit length instead of meters. Note: g = 32 ft/s2. Estimate (a) Estimate the maximum speed a rider might have at location . 32 ft/s 32 ft/s Your value is acceptable. (b) For the speed you estimated in part (a), using Conservation of Energy, determine the maximum height the rider can rise up to as he goes up the vert. 16 ft 16 ft Calculations (c) For the rest of this problem consider just the motion of the center of mass of the rider. Consider a standard half-pipe with h = 13 ft with a 4 ft vert. Consider a 5.5 ft person whose center of mass is at his midheight. He starts from rest at location . What is his speed v2 at location if he does not crouch (his center of mass is at the same height relative to his feet)? (d) Based on your answer in part (c) above, how high (what is the location of his center of mass relative to location ) will he go up the vert on the other side? (e) If he wishes to go up beyond the edge of the vert, he will need to have greater kinetic energy when he is at location . To do this, the rider will pump as he goes back and forth on the half-pipe several times (he will crouch down as he approaches the flat to lower his center of mass) to further decrease his potential energy then spring back up to convert his internal muscular energy to kinetic energy. Suppose the rider in this case wishes to rise above the edge of the vert so that the change in his center of mass position is 20 ft relative to the flat section of the pipe (location ), what speed does he need to have when he is at location ? (f) In solving this problem we have made certain assumptions and approximations. Which of the following statements is true?i. The rider will start rotating as he approaches the highest point above the vert but this does not appreciably affect the mechanical energy of the rider. ii. The rider and his skateboard are considered to be one object. iii. You are correct in assuming that the rider's moment of inertia does not change. iv. It is assumed that the rider has only translational kinetic energy and potential energy

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The rider starts from rest at location at the edge of the in-ramp and goes down the transition. Typi...
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