When a table tennis ball is completely immersed in water, its buoyancy changes from moving to resting after letting go () A. Buoyancy keeps increasing, but it is less than gravity. B. buoyancy keeps unchanged, but buoyancy is greater than gravity. C. buoyancy keeps unchanged at first, then decreases, and is always greater than gravity. Until it finally comes to rest, buoyancy is equal to gravity. D. buoyancy is greater than gravity first, and then less than gravity

When a table tennis ball is completely immersed in water, its buoyancy changes from moving to resting after letting go () A. Buoyancy keeps increasing, but it is less than gravity. B. buoyancy keeps unchanged, but buoyancy is greater than gravity. C. buoyancy keeps unchanged at first, then decreases, and is always greater than gravity. Until it finally comes to rest, buoyancy is equal to gravity. D. buoyancy is greater than gravity first, and then less than gravity

According to f = ρ GV row, we can know that: when the table tennis ball starts to rise to the surface of the water, the volume of the boiled water discharged by the table tennis ball remains unchanged, and the buoyancy received by it remains unchanged; when the table tennis ball starts to appear on the surface of the water, the volume of the boiled water discharged becomes smaller, and the buoyancy received decreases. When the ball is still, it is in a floating state, and the gravity and buoyancy of the ball are equal, so the table tennis ball is affected before it is still The buoyancy of C

The volume of an object is 0.4dm cubic meter. What is its buoyancy when it is completely immersed in water? If the neutral of the object is 3N, what is its buoyancy in water?
G is 10N / kg

The first step: first convert the volume unit into square meter, and then substitute it into Archimedes principle
Part 2: according to the gravity and the volume of the object, the density of the object is smaller than that of the water. If we know that the object will float in the water, the buoyancy is equal to the gravity of the object itself 3N

When a metal ball with a mass of 250g and a volume of 300cm is put into water, how much buoyancy does it receive when it is still?

Answer: 2.5n
Analysis:
ρ matter = m / v = 250 / 300 ≈ 0.83g/cm & # 179; < ρ water
Therefore, the object is floating in the water, and the buoyancy of the floating object is equal to its own gravity
Therefore: F = g = m, M = 250g = 0.25kg
＝0.25×10
＝2.5N

How much buoyancy does a 0.1dm cubic Mukuai get when it is completely immersed in water? After letting go, will the ball float or sink
What is the state of the ball when it is still? What is the buoyancy at this time
Let's make a formula

According to Archimedes' law, f floating = ρ liquid * g * V row
After letting go, the block is subjected to vertical upward buoyancy (f floating = ρ water * g * V wood) and vertical downward gravity (g = ρ wood * g * V row). As ρ water > ρ wood, f floating > G, so the block should float up
When the block is still, its stress should be such that the buoyancy of the block is equal to its gravity, that is: F floating '= ρ water * g * V row = g = ρ wood * g * V row
Is the answer satisfactory?