Question

(a) Define buoyant force. Name two factors on which buoyant force depends.

(b) What is the cause of buoyant force ?

(c) When a boat is partially immersed in water, it displaces 600 kg of water. How much is the buoyant force acting on the boat in newtons ? (g = 10 m s^-2 )

Answer 1

(a) The upward force acting on an object immersed in a liquid is called buoyant force. Factors affecting buoyant force: 

(i) Volume of object immersed in the liquid, 

(ii) Density of the liquid. 

(b) The cause of buoyant force is the greater upward pressure exerted by water underneath the object.. 

(c) Mass of water displaced = 600kg 

Weight of water displaced, W =m x g 

=600 x 10 =6000N 

Since, the weight of water displaced by the boat is 6000N, therefore the buoyant force acting on the boat will also be 6000N.