Question

If you drop a piece of ice on a hard surface, the energy of impact will melt some of the ice. The higher it drops, the more ice will melt upon impact.

Find the height from which the a block of ice should ideally be dropped to completely melt if that falls without air drag. [Hint: Equate the joules of gravitational potential energy to the product of the mass of ice and its heat of fusion (in si units, 335,000 J/kg. Do you see why the answer doesn't depend on mass?] Express your answer to two significant figures and include the appropriate units.

B: Does the answer depend on mass?

Answer 1

`3.4*10^(4)` m

B. No.

Step-by-step explanation:

mgh = mLf

mgh is the gravitation potential energy and mlf is the product of the mass of ice and its heat of fusion.

Where,

m is the mass

g is the acceleration of gravity

h is the height of drop

and Lf is the heat of fusion of ice

since the masses on both side of the equation can be cancelled out (also the reason to part B of the question), we are left with

gh=Lf

h=Lf/g

`h = (335,000 J/kg)/(9.81 m/s^2)  = 3.4 *10^(4) m`