(Physics) Chapter 13: Liquids

30N

A 3 Liter container of mercury has a mass of 40.8 kg and weighs 399N. When it is fully submerged in water, what is the buoyant force acting on it? (Density of water= 1 kg/ Liter or 1 g/ mL

Look on 13.4 HW for the force diagram. Fnet= -2.44N

A solid object has a volume of 56 mL and is fully submerged. It weighs 3N. Draw a force diagram for the object when in water and calculate the Fnet.

Fw of water displaced= -0.56, Fb= 0.56 N

A solid object has a volume of 56 mL and is fully submerged. What is the weight of the water displaced? What is the buoyant force?

56 mL

A solid object has a volume of 56 mL and is fully submerged. What volume of water does the object displace?

14N

An object weighs 20N in air. It displaces 14N of water when fully submerged.

93250 Pa or N/m^2

Calculate the pressure exerted by a 600N woman if she is standing on one foot and the area of her shoe is 0.0064 m^2.

49,000 Pa

Calculate the water pressure that acts on the bottom of an object when the bottom is at a depth of 5 meters of fresh water. (Weight Density of Water, wD= 9800)

Yes, pressure will increase because depth increases.

Does the diver experience a change in pressure? If so, why? Diver A is diving in a freshwater lake and changes his depth from 10 ft. to 20 ft.

No, pressure will remain the same because both waters have the same density and the depth does not change.

Does the diver experience a change in pressure? If so, why? Diver B is diving in Creve Coeur Lake at a depth of 10 feet and then travels to Lake Michigan where he dives at a depth of 10 feet.

Yes, there will be more pressure in the Atlantic Ocean because salt water has a higher density than fresh water.

Does the diver experience a change in pressure? If so, why? Diver C is diving in Lake Michigan at a depth of 10 feet and then travels to the Atlantic Ocean where he dives at a depth of 10 feet.

The object will always be displacing the same weight of water.

Explain why as the object sinks, the buoyant force will remain constant.

An object that is floating must have a net force of zero because it is at rest.

Explain why it is impossible for an object that is floating to experience a buoyant force of 13 N if its weight is only 12 N.

0.453 kg

How many kilograms in 453 grams of slime?

Check #9 on test review for force diagram, Fb= 4N, The object will sink because there is a downward NET FORCE.

I hold an object that weighs 8N underwater and it displaces 4N of water. What is the buoyant force on the object? Draw a force diagram. Will it sink, float, or rise.

39200 N

If I fully submerge a 4 m^3 object, how much weight of water will it displace?

V= 4 m^3

If I fully submerge a 4 m^3 object, what volume of water will it displace?

3920 kg

If I fully submerge a 4 m^3, what mass of water will it displace?

Check on #11 (b) on the test review

If I have a lump of clay that has a weight of 3N and form it so that it will float, draw a force diagram

Fnet=0 because it's floating

If I have a lump of clay that has a weight of 3N and form it so that it will float, what is the net force?

Fw of water= -4N

If I have a lump of clay that has a weight of 3N and form it so that it will float, what weight of water will it displace?

Fb= 4N

If I have a lump of clay that has a weight of 3N and form it so that it will float, what will the buoyant force be?

34300 N/m^2 or Pa

If I submerge an object in fresh water to a depth of 3.5 meters, what is the pressure exerted on that object? (Weight density of water= 9800 N/m^3)

The clay ball will not displace the same weight in water because it will have a lower volume. The buoyant force will be lower.

If I take that same lump of clay (that was once in a form that made it float) and roll it into a ball, it still weighs 3N of water but no longer floats. Will it displace the same weight of water? Will the buoyant force be the same?

-25N

If a 4.6 kg object displaces 2.5 L of water, what will the water weigh?

The weight of the water would equal the weight of the object. 400 N

If the floating object weighs 400N, what weight of water does it displace?

18,120 N/ m^3

If you make 453 grams of slime that can completely fill a 250 mL (0.00025 m^3) canister. Calculate the weight density in N/m^3

1.812 g/mL

If you make 453 grams of slime that can completely fill a 250 mL (0.00025 m^3) canister. What is the density of your slime?

-4.53 N

If you make 453 grams of slime that can completely fill a 250 mL (0.00025 m^3) canister.How much does the slime weigh?

No, you are still floating and have a net force of zero! Your weight is the same in both places. It takes less or the more dense water to hold you up!

If you were to float in the Dead Sea, you would float appreciably higher than in fresh water because the Dead Sea's water has a greater density. Would the buoyant force on you be greater? Why or why not?

-2.44N

If you were to pick the object up and hold it under the water, what would be it's apparent weight?

The weight of the water displaced.

In order to determine the buoyant force acting on an object, what do you need to know?

The buoyant force would be the same because the pressure difference between the top of the object and the bottom of the object would be the same.

Is there more buoyant force on an object that is fully submerged near the surface of the liquid or fully submerged near the bottom of the liquid.

There is more pressure on the object near the bottom because it is deeper.

Is there more pressure on an object that is fully submerged near the surface of the liquid submerged near the bottom of a liquid?

A person lying down all exert less pressure because the weight s distributed over a larger area.

Which exerts less pressure on the floor? A person standing or the same person lying down? Explain.

Glass 2 will exert more pressure because the weight is applied by a smaller area.

Which of the following dinner glasses both filled with exactly the same volume of water will exert greater pressure on the bottom of the glass and why? Glass 1- shorter and wider Glass 2- taller and narrower

The pressure is greater on the bottom (deeper) part of an object than the top. There will always be more force on the deeper end of the object than the top of the object because the pressure is greater on the bottom than the top. These forces combined will always produce a net force upward.

Why does Fb act upward?

The buoyant force is equal to the weight of the water displaced. A fully submerged object displaces more water.

Why is the buoyant force greater when an object is fully submerged rather than only partially submerged?

Sink. This object is more dense than water.

Would this object sink or float in water? Density= 2.6 g/mL

The object will float because net force is zero.

Would this object sink or float in water? Fw= 12N, displaces 12N of water

The object will rise because of an upward net force.

Would this object sink or float in water? Fw= 40N, Fb= 54N

This object will rise because the buoyant force calculates to be 2N! There will be a net force upwards.

Would this object sink or float in water? V= 200 mL, Fw= 1.6 N, simple toy underwater

The aluminum because it is less dense and would have the greater volume- displacing a greater weight of water.

You hold 1 kg block of aluminum and a 1kg block of irony fully submerged in water. If you let go they both will sink. Which has a greater buoyant force acting on it? Why?

Net force is zero

Wha is the net force on a floating object?

The pressure of the fluid will be greater on the bottom of the object than on the top. An upward buoyant force.

What about a fluidity causes a buoyant force on objects that are immersed in that fluid.

The buoyant force is equal to the weight of WATER displaced by the object. Fb= Fw of the water displaced

What is Archimedes Principle?

Pressure is transmitted undiminshed throughout a liquid. P in=P out. Liquids are incompressible.

What is Pascal's Principle?

Only when floating, the buoyant force is equal to the weight of the object itself

What is Principle of Flotation?

Depth of the liquid multiplied by weight density [N/m^2 or Pa (pascal)]

What is liquid pressure?

Force per unit area P= F/a [N/m^2]

What is pressure

-6N

What is the apparent weight of the object underwater?

An object displaces a volume of water equal to its own volume.....when fully submerged. V of the water= V of the object

What is the volume rule?

Depth. Weight density.

What two things affect the amount of liquid pressure exerted at the base of a dam?