I believe that answer is nitrogen.
The average velocity of Sandy is given by the total distance covered S divided by the total time taken t:

The total distance covered is

while the total time taken is 2 hours + half an hour (for the rest) + 1 hour and half, so

Therefore, the average velocity is
Answer: 
Explanation:
Given
Mass of water is 
mass of ice is 
Latent heat of fusion 
The heat capacity of water is 
Suppose water is at
and it reaches to
to melt the ice
the heat released by water must be equivalent to heat absorbed by the ice

Streamline
Effect
Drag
Parachutes
Surface area
Friction
Air
Water