Question
An ice cube falls from a height of 1500m. Assuming that whole of potential energy of ice cube converts into heat, find the fraction of mass of ice that melts.
Take g = 10m/s2and J = 4.2cal.
Solution
Let M be the mass of ice cube.
The mass of ice that melts on falling = n
The potential energy that converts into heat is given by,
E= Mgh = M x 1500 x 10
= 15000M Joule
Heat required to melt m gram of ice is,
Q = mL = m x 80,000 cal
= m x 80,000 x 4.2 Joule
Since whole of potential energy is converted into heat and used to melt the ice, therefore
Q = E
m x 80, 000 c 4.2 = 15, 000M
is the fraction of ice that melts.
The mass of ice that melts on falling = n
The potential energy that converts into heat is given by,
E= Mgh = M x 1500 x 10
= 15000M Joule
Heat required to melt m gram of ice is,
Q = mL = m x 80,000 cal
= m x 80,000 x 4.2 Joule
Since whole of potential energy is converted into heat and used to melt the ice, therefore
Q = E
m x 80, 000 c 4.2 = 15, 000M is the fraction of ice that melts.
