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17. II A speed skater moving to the left across frictionless ice at 8.0 m/s hits a 5.0-m-wide patch of rough ice. She slows steadily, then continues on at 6.0 m/s. What is her acceleration on the rough ice?19. || A car starts from rest at a stop sign. It accelerates at 4.0 mlsz for 6.0 s, coasts for 2.0 s, and then slows down at a rate of 3.0 rm's2 for the next stop sign. How far apart are the stop signs? 23. || When jumping, a flea accelerates at an astounding 1000 misZ, BIO but over only the very short distance of 0.50 mm. If a flea jumps straight up, and if air resistance is neglected (a rather poor ap- proximation in this situation), how high does the flea go? 25. III A rock is dropped from the top of a tall building. The rock's displacement in the last second before it hits the ground is 45% of the entire distance it falls. How tall is the building