The figure shows a 0.41-kg block sliding from A to B along a frictionless surface. When the block reaches B, it continues to slide along the horizontal surface BC where the kinetic frictional force acts. As a result, the block slows down, coming to rest at C. The kinetic energy of the block at A is 37 J, and the heights of A and B are 12.0 and 7.0 m above the ground, respectively. Concepts: (i) Is the total mechanical energy of the block conserved as the block goes from A to B? Why or why not? (ii) When the block reaches point B, has its kinetic energy increased, decreased, or remained the same relative to what it was at A? Give a reason for your answer. (iii) Is the total mechanical energy of the block conserved as the block goes from B to C? Justify your answer. Calculations:
(a) What is the value of the kinetic energy of the block when it reaches B?
(b) How much work does the kinetic frictional force do during the BC segment of the trip? |

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