A 79−$79-$kg base runner begins his slide into second base when he is moving at a speed of 3.5$3\mathrm{.}5$ m/$/$s.$.$ The coefficient of friction between his clothes and Earth is 0.70.$0\mathrm{.}70.$ He slides so that his speed is zero just as he reaches the base.

($($a)$)$ How much mechanical energy is lost due to friction acting on the runner?

 

($($b)$)$ How far does he slide?