Calculating Buoyant Force: Ice in Water

In summary, the buoyant force on 0.70 kg of ice floating freely in liquid water is equal to the weight of the water displaced. To find the buoyant force on 0.70 kg of ice held completely submerged under water, the density of water can be used since the density of ice is similar. The equation for the buoyant force is (rho)(gravity)(volume).
  • #1
Jtappan
96
0

Homework Statement



(a) What is the buoyant force on 0.70 kg of ice floating freely in liquid water?
_____ N upward

(b) What is the buoyant force on 0.70 kg of ice that is held completely submerged under water?
______N upward

Homework Equations



?

The Attempt at a Solution



How do you calculate the buoyant force of an object in another object as it states here?
 
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  • #2
The buoyant force is equal to the weight of the water displaced. Is that enough to get started?
 
  • #3
The buoyant force is equal to the weight of the water that is displaced.
If we look at the first problem, we can see that it's in equilibrium, which means all the forces are equal. Should be easy to solve the first one now.

The second one, I think you have to assume that the ice's density is the same as the waters. Because just from the mass, that doesn't help us. A 0.70kg piece of gold will have far less buoyant forces than a 0.70kg piece of ice. Since there's no other information here, we'll have to assume the ice's density.
 
  • #4
Objects will sink until the bouyant force is equal to the object's weight. The size of the bouyant force is equal to the weight of the displaced water.
 
  • #5
ok i got the first one, now i am still confused on how to find it if it is held under the water.
 
  • #6
Density = mass/volume
You should know the density of water.

The density of ice is more, but using the density of water should be alright here. Unless they've given you it's density.
 
Last edited:
  • #7
so it is the density of water = mass of ice cube/volume of ?? what
 
  • #8
Volume of the ice cube, if it's density were equal to that of water, which it almost is.
Then refer back to the question with your new information, and you can solve it.
 
  • #9
i am still not getting the right answer..I put it into the equation (rho)(gravity)(volume)
 
  • #10
got it.. thanks everyone for the help!
 

1. What is the definition of buoyant force?

Buoyant force is the upward force exerted on an object when it is submerged in a fluid, such as water or air. It is equal to the weight of the fluid that the object displaces.

2. How does the buoyant force of ice in water differ from other objects?

The buoyant force of ice in water is unique because ice is less dense than water. This means that when ice is submerged in water, it displaces less water than its own weight, resulting in a lower buoyant force compared to other objects.

3. How does the buoyant force of ice in water affect icebergs?

The buoyant force of ice in water allows icebergs to float. Since the buoyant force is equal to the weight of the displaced water, the larger the iceberg, the more buoyant force it has and the higher it will float in the water.

4. How does the buoyant force of ice in water relate to Archimedes' principle?

Archimedes' principle states that the buoyant force on an object is equal to the weight of the fluid it displaces. This applies to ice in water, as the buoyant force on the ice is equal to the weight of the water that it displaces.

5. How does the buoyant force of ice in water affect ships?

The buoyant force of ice in water can be a concern for ships, especially in icy waters. If a ship collides with an iceberg, the buoyant force of the iceberg can cause damage to the ship's hull. Additionally, ice formation on the ship's hull can increase its weight and decrease its buoyancy, affecting its stability in the water.

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