what will happen? they want to occupy that very volume of that less densy invader! in all possible directions. and there's something less dense than them. so all the water molecules in the sea are pushed down.

then the sea itself has a mass thus weight by gravity. Then what pushes the object upward (and any-wards)? the whole water itself and its weight by gravity. as much as we don't consider a freefalling ball in air as having any reaction force from any surfaces, even though it keeps contacting with air pressure (this is a buoyant force too)

In the case of a ball in water, we don't treat water or whatever fluid around it as another object. Reaction force (normal force in the case of gravity) only works when two objects meet on a surface buoyant force is different from reaction force 2 0 kg ) g (Plug in numbers. Convert diameter to radius!) F, start subscript, T, end subscript, equals, left parenthesis, 1, point, 23, start fraction, start text, k, g, end text, divided by, start text, m, end text, cubed, end fraction, right parenthesis, open bracket, start fraction, 4, divided by, 3, end fraction, pi, left parenthesis, start fraction, 3, point, 50, start text, space, m, end text, divided by, 2, end fraction, right parenthesis, cubed, close bracket, g, minus, left parenthesis, 9, point, 20, start text, space, k, g, end text, right parenthesis, g, start text, left parenthesis, P, l, u, g, space, i, n, space, n, u, m, b, e, r, s, point, space, C, o, n, v, e, r, t, space, d, i, a, m, e, t, e, r, space, t, o, space, r, a, d, i, u, s, !, right parenthesis, end text

Find force at bottom of closed tank