How Much Force Is Needed to Keep a Beach Ball Underwater?

[jsalapide]

1.A beach ball has a volume of 0.050 m^3. How much force would you have to exert to hold this beach ball completely under water?

can somebody help me plss,,,,

 

[redargon]

what have you tried so far?

There is a template for homework questions and a separate section.

 

[jsalapide]

I learned that for an object that is completely submerged in a liquid, the density of the object is equal to the density of the liquid.

I used the formula p=m/v to get the mass of the ball. I set p as the density of water which is 1000 kg/m^3. The answer I got was 50 kg. Then I multiply it to 9.8 m/s^2 to get the buoyant force.

My answer was 490 N...

Am I correct?

 

[PhanthomJay]

I learned that for an object that is completely submerged in a liquid, the density of the object is equal to the density of the liquid.

This is not correct. Look up Archimedes principle.

I used the formula p=m/v to get the mass of the ball. I set p as the density of water which is 1000 kg/m^3.

For all practical purposes, the density of the air filled beach ball can be neglected...that is, assume it has no weight.

The answer I got was 50 kg. Then I multiply it to 9.8 m/s^2 to get the buoyant force.

My answer was 490 N...

Am I correct?

The buoyancy force is 490N upward. What downward force must be applied to keep the ball completely underwater?