A block of wood weighs 40 N in air and 30 N in water. What is the buoyant force exerted by water on the block?
B = -F_g
= B-F_g
=30-40
= - 10N
Is this correct?
No, the calculation you have provided is not correct. To determine the buoyant force exerted by water on the block, you need to use Archimedes' principle. Archimedes' principle states that the buoyant force on an object submerged in a fluid is equal to the weight of the fluid displaced by the object.
To find the buoyant force, you need to first determine the weight of the water displaced by the block. The weight of the water displaced is equal to the weight of the block in air minus the weight of the block in water.
Given that the weight of the block in air is 40 N and the weight of the block in water is 30 N, the weight of the water displaced can be calculated as follows:
Weight of water displaced = Weight in air - Weight in water
Weight of water displaced = 40 N - 30 N
Weight of water displaced = 10 N
Therefore, the buoyant force exerted by the water on the block is 10 N.