A stationary object at 4° C and weighting 3.5 kg falls from a height 2000 metres on snow mountain at 0° C. If the temperature of the object at the strike is 0°  C (g=10 m s-2), then amount of ice melted is:(Latent heat of fusion of ice=3.5×105J/kg)

From Joules law: W=JQ⇒mobject gh = mice melted L   Initially body has potental energyi.e work is stored in the form of potentential energy& during conversion of state, Q=mL  Here m is mass g is acceleration due to gravity =10 m s-2h is height of fall =2000mL is latent heat of fusio of ice=3.5x105Jkg-1   substitute above values, (3.5)(10)(2000)=mice(3.5x105)mice=(3.5)(10)(2000)3.5x105kg ⇒mice=(3.5)(10)(2000)3.5x105x1000 g ⇒mice=200 g= mass of ice that melted