Answer:
Explanation:
Given
Mass of ice 
mass of water 
Initial Temperature of water 
Let T be the Final Temperature of mixture
Latent heat of Fusion 
heat required to melt ice completely is

Heat released by water is taken by ice thus



Answer:
External force on him will be 112 N
Explanation:
We have given the mass of the sprinter m =70 kg
Acceleration of the sprinter 
We have to find the net external force
According to second law of motion force = mass ×acceleration
Force is dependent on the mass and acceleration
So 
So external force will be 112 N
The blades that spin around in the fan, because they are flat and produce work