Question

A stone weighs 25 N in air and 12 N when immersed in water.The magnitude of buoyant force acting on the stone in water is
1) 13 N
2) 25 N
3) 12 N
4) 37 N

Answer 1

weight in air = 25 N

weight in water = 12 N

so the buoyant force acting on stone is difference of its weight in air and water

25 N - 12 N

= 13 N