Answer:

Explanation:
From the question we are told that:
Velocity of water 
Height=?
Generally, the equation for Water Velocity is mathematically given by

Therefore Height h is given as



Water can freeze in cold weather and cause brake failure.
Answer:
80grit
Explanation:
80 grit is coarsest grit that may be used on aluminum
The lowest grit sizes range from 40 to 60. From the given options 80 grit is practically available grit.
What is a sandpaper used for?
They are essentially used for surface preparation. Sandpaper is produced in a range of grit sizes and is used to remove material from surfaces, either to make them smoother (for example, in painting and wood finishing), to remove a layer of material (such as old paint), or sometimes to make the surface rougher (for example, as a preparation for gluing).