Asubmarine is 50 m below the surface of the ocean and its weight is exactly balanced with the thrust. if it descends to 100 m and stops, the buoyant force (thrust) (a) does not change
(b) decreases
(c) increases
(d) cannot be determined
(e) the direction is reversed
and why?

(a)does not change

Explanation:

Given

Submarine is 50 m below the surface

Now submarine descends to 100 m and stops

As we know that pressure difference at a depth of h is given by

where =Density of fluid

g=acceleration due to gravity

h=height below free surface of liquid

buoyant force is equal to volume displaced by object

as the submarine is already in water therefore buoyant force will remain same.

probably not if net force is zero

increase masses, decrease separation