Question

Assertion: To float; a body must displace liquid whose weight is equal to the actual weight.
Reason: The body will experience no downward force in that case.
A. Both assertion and reason are true and reason is the correct explanation of the assertion.
B. Both assertion and reason are true but reason is not the correct explanation of assertion.
C. Assertion is true but reason is false.
D. Both assertion and reason are false.

Answer 1

Hint: Refer to Archimedes principle to answer this question. The net upward force for the floating body is provided by the buoyant force due to the liquid.

Complete step by step answer:
According to Archimedes principle, the upward thrust or buoyant force exerted on the floating body completely or partially immersed in a liquid is equal to the weight of the liquid displaced by the body.
Therefore, the assertion is $true.$

Since the body is floating, the weight of the body is balanced by the upward buoyant force. Therefore, the net force on the body is zero. If there is net downward force on the body, the body will sink in the liquid.
Therefore, the reason is also $true.$

So, the correct answer is “Option A”.

Note:
If the body is sinking, the net downward force is greater than the upward thrust provided by the buoyant force. In that case, the weight of the liquid displaced by the body is equal to the buoyant force.