A 50 kg log floats down the river. What is the buoyancy force acting on this log?

If the buoyancy force is less than the weight of the log, then it will sink. If it is equal to the weight of the log, the log will float. If more – the log will float, protruding above the water surface. We are satisfied with the second and third cases. Let us write down the inequality reflecting both cases: (let “> =” denote “greater than or equal to”) F (a)> = mg; F (a)> = 50kg * 9.8m / s ^ 2; F (a)> = 490H.
Answer: the force is greater than or equal to 490 N.