A block of ice of mass $$50$$ kg is sliding on a horizontal plane. It starts with speed $$5$$ $$ms-1$$ and stops after moving through some distance. The mass of ice that has melted due to friction between the block and the surface is (Assuming$$ that no energy is lost and latent heat of fusion of ice is $$80$$ cal g $$-1$$ , J $$=$$ $$4.2$$ J $$cal-1)

Question

Infinity Learn · Accepted Answer

Given,   $$m=50kg$$,$$v=5ms$$−$$1$$,$$L=80calg$$−$$1J=42Jcal$$−$$1$$ and $$m=$$?Heat lost, i.e. $$Q1$$ $$=$$ work done $$=$$ K $$(kinetic$$ $$energy)=12mv2=12$$×$$50$$×$$52=625Jand$$ heat gained, i.e.   $$Q2=m$$'×$$L=80$$×m'×$$4.2$$∵   $$Q1$$  $$=$$  $$Q2625=m$$'×$$8$$×$$42$$⇒m'$$=1.86g$$

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