Question

A boy carries a fish in one hand and a bucket (not full) of water in the other hand. If he places the fish in the bucket, the weight now carried by him (assume that water does not spill):
A. Is less than before
B. Is more than before
C. Is the same as before
D. Depends upon his speed

Answer 1

Hint:The force that comes into play in this solution is the buoyant force.
The upward thrust exerted by a fluid countering the weight of an object immersed in a fluid is the buoyant force. Buoyant force may be exerted on an object that is fully or partially immersed. The density of the immersed fluid is directly proportional to the buoyancy.

Complete answer:
Buoyant force is unavoidable. This is due to the reason that in a fluid, the base of an object is usually lower than the object’s top. This implies that the force acting upwards would be stronger than the force downward from water.

On each submerged object, including those that sink, there is certainly an upward buoyant force. The weight of the sinking object is greater than the buoyant force, so they sink. If the weight is less than the objects would float on water.

The famous Archimedes principle is related to buoyant force which states that the buoyant force on an object is equal to the weight of the fluid displaced by the object. It is given in the question that a boy carries a fish in his one hand and a bucket (not full) of water in his other hand. We have to find out what will be the weight of the bucket when he places the fish in it by using the above observations.

When the boy puts the fish in the bucket buoyant force will act on it. But the water height will also rise at the same time which will raise the water pressure at the bucket’s edge. The force created by the increased pressure will balance out the buoyancy force. Thus, the weight will remain the same as before.

Hence, option C is correct.

Note:Here we have to pay attention to the question; it may be confusing as to why the weight will remain the same even when the water does not spill. But here water pressure will increase, so the buoyant force will even out.