Compare the liquid pressure at the surface of a swimming pool and the bottom of the swimming pool

The pressure difference is equal to the product of density , height and g

Given that h is height difference between bottom and surface of a pool

P  

b

​  

−P  

s

​  

=dgh

Density d of water is 1

So we get P  

b

​  

−P  

s

​  

=gh

Therefore option A is correct

Explanation:

work: w = fd (given)

work done by chet   =50*1 = 50 j

work done by mika =40*2 = 80 j

work done by sara =30*1.5 = 45 j

work done by bill =60*0.5 = 30 j

students in order from the greatest amount of work done to the least is mika> chet> sara> bill

hence option (b) is correct.

none, its a machine