Hailstones fall from a certain height. If they melt completely on reaching the ground, find the height from which they fall.(g = 10 ms-2, L = 80 calorie/g and J = 4.2J/calorie).

Hailstones fall from a certain height. If they melt completely on reac

1.	Hailstones fall from a certain height. If they melt completely on reaching the ground, find the height from which they fall.(g = 10 ms-2, L = 80 calorie/g and J = 4.2J/calorie).
Answer» Solution :On reaching the ground a hailstone of MASS M loses potential energy which is CONVERTED into heat energy REQUIRED to melt it. In SI, potential energy lost = heat energy required for MELTING the hailstone `Mgh=ML rArr g h=L` `h=(L)/(g) , h=(80xx4.2xx1000)/(10)` `=33.6 xx1000m=33.6km`.