solution: part a.

Reference for potential energy is the initial height of the block.

 Initial Conditions: all the energy is KE because the height is 0, so PE is 0

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Friction works against motion:

eqnarray12

Energy is also converted to potential energy:

eqnarray14

We need to find d where frictional energy lost and the Potential Energy gained equal the initial kinetic energy.

eqnarray16

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