A doubt regarding law of floatation The condition for flotation of a body a little bit above the surface of the liquid is that the upthrust force must be greater than its weight. Why do we in numericals take upthrust equal to the weight of the body?
In my college textbook, it says that a body which floats partially submerged has Fb>W(buoyant force>weight of the body)but everywhere else as in numericals I see that since the body is floating Fnet=0 and body is at equilibrium so Fb=W.Isn't it contradicting?
Please clear my doubt asap as I have many sleepless nights.
 A: Floating actually means to rest or cause to rest on the surface of a fluid or in a fluid or space without sinking.
That means the object should be on the surface or to come up of the surface after putting some external force on the body and leaving it
[edit added:] That is, the body when underwater experiences net force upwards, but once the net forces are zero, it floats with a certain portion above the water's surface [end edit]
The case for which,
$F_b = Mg$
it means that the body is floating and is at the rest at the same time.
And for
$F_b > Mg$
Here, the net force in the upward direction
This means the object is willing to come at the $surface$ until both the forces becomes equal. Which can also be categorized as a case of floating.
But on the other hand if
$Mg > F_b$
That means Net force is in the direction the gravitational force.
Then the object will always tends to sink it will never come out by itself on the surface even though if we pull it out by the force applied by an external agent it will still tend to sink. that's just the case.
