The mechanical equivalent of heat is `4.2 xx 10^(7) erg cdot cal^(-1)`. What does it mean?

Define mechanical equivalent of heat. What is its value?

What do you mean by mechanical equivalent of heat ?

Find out the minimum height from which a piece of ice at 0^(@)C should be dropped so that it melts completely. Assume that 50% of the energy lost due to its fall is responsible for the fusion of ice. J = 4.2 xx 10^(7) erg cdot cal^(-1) , latent heat of fusion of ice = 80 cal cdot g^(-1) .

Find out the minimum height from which a piece of ice should be dropped to the ground so that it melts completely. Assume that 20% of energy is lost. J = 4.2 xx 10^(7) erg cdot cal^(-1) and latent heat of fusion of ice = 80 cal cdot g^(-1) .

1 kg oil is taken in a copper calorimeter having mass 100 g. This oil is stirred vigorously by applying a torque of 10^(8) dyn cdot cm with the help of a rotating paddle. The temperature of the oil rises by 5^(@)C after 220 rotations. Determine the mechanical equivalent of heat. Specific heat of copper = 0.09 cal cdot g^(-1) cdot^(@)C^(-1) and specific heat of oil = 0.64 cal cdot g^(-1) cdot^(@)C^(-1) .

Specific heat of argon at constant pressure and at constant volume are 0.12 cal cdot g^(-1) cdot^(@)C^(-1) and 0.08 cal cdot g^(-1) cdot^(@)C^(-1) respectively. Find out the density of argon at STP. J = 4.2 xx 10^(7) erg cdot cal^(-1) , standard pressure = 1.01 xx 10^(6) dyn cdot cm^(-2) .

A lead bullet stopped on hitting an iron plate at a velocity of 300 m cdot s^(-1) . Find out the rise in temperature of the bullet, if the heat evolved is shared equally between the bullet and the plate. Given, J = 4 cdot 2 xx 10^(7) erg cdot cal^(-1) , specific heat of lead = 0.03 cal cdot g^(-1) cdot^(@)C^(-1) .

Water drops from a height of 50 m in a waterfall. Find out the rise in temperature of water, if 75% of its energy is converted into heat and absorbed by water. (J = 4.2 xx 10^(7) erg cdot cal^(-1) , g = 9.8 m cdot s^(-2))

Find out the amount of work done to convert 100 g ice at 0^(@)C to water at 100^(@)C . (Latent heat of fusion of ice = 80 cal cdot g^(-1) , mechanical equivalent of heat = 4.2 J cdot cal^(-1)) .

What is the value of mechanical equivalent of heat in CGS system?