1.
Water pressure is greatest against the
Correct Answer
B. Bottom of a submerged object.
Explanation
The water pressure is greatest against the bottom of a submerged object because the weight of the water above it creates a force that pushes down on the object. As the depth increases, the pressure also increases due to the increasing weight of the water column. Therefore, the bottom surface of the submerged object experiences the highest pressure compared to the other surfaces.
2.
A dam is thicker at the bottom than at the top partly because
Correct Answer
B. Water pressure is greater with increasing depth.
Explanation
The correct answer is "water pressure is greater with increasing depth." This is because the weight of the water above increases with depth, resulting in higher pressure at deeper levels. As a dam needs to withstand this pressure, it is designed to be thicker at the bottom to provide stability and prevent any potential breaches or structural failures.
3.
The pressure in a liquid depends on liquid
Correct Answer
C. Both of these
Explanation
The pressure in a liquid depends on both liquid density and depth. The density of a liquid determines how closely packed its particles are, and therefore how much mass is present in a given volume. The depth of a liquid affects the pressure because the weight of the liquid above a certain point increases with depth, resulting in higher pressure. Therefore, both the density and depth of a liquid play a role in determining the pressure within it.
4.
The pressure at the bottom of a jug filled with water does NOT depend on
Correct Answer
D. Surface area of the water.
Explanation
The pressure at the bottom of a jug filled with water does not depend on the surface area of the water. The pressure at a certain depth in a fluid is determined by the weight of the fluid above it. The weight of the fluid depends on the density of the fluid and the height of the fluid column. The acceleration due to gravity affects the weight of the fluid, but it does not directly affect the pressure at a certain depth. Therefore, the surface area of the water does not affect the pressure at the bottom of the jug.
5.
One liter of water has a mass of
Correct Answer
A. 1 kilogram.
Explanation
The density of water is 1 gram per milliliter, which means that 1 liter of water has a mass of 1000 grams or 1 kilogram. Therefore, the correct answer is 1 kilogram.
6.
The mass of a cubic meter of water is
Correct Answer
D. 1000 kg.
Explanation
The mass of a cubic meter of water is 1000 kg because the density of water is 1000 kg/mÂ³. Density is defined as mass divided by volume, and since the volume of a cubic meter is 1 mÂ³, the mass of water in a cubic meter is also 1000 kg.
7.
Pumice is a volcanic rock that floats. Its density is
Correct Answer
A. Less than the density of water.
Explanation
Pumice is a type of volcanic rock that is formed when lava with high gas content solidifies quickly. The gas bubbles trapped within the rock make it porous and lightweight, causing it to have a lower density than water. This is why pumice floats on water. Therefore, the correct answer is "less than the density of water."
8.
The reason that buoyant force acts upward on a submerged object is that
Correct Answer
D. Upward pressure against the bottom is greater than downward pressure against the top of the submerged object.
Explanation
The correct answer is that upward pressure against the bottom is greater than downward pressure against the top of the submerged object. This is because when an object is submerged in a fluid, the fluid exerts pressure on the object from all directions. The pressure at the bottom of the object is greater than the pressure at the top due to the weight of the fluid above it. This imbalance in pressure creates a net upward force, known as the buoyant force, which acts against the force of gravity and causes the object to float.
9.
A completely submerged object always displaces its own
Correct Answer
A. Volume of fluid.
Explanation
When a completely submerged object is placed in a fluid, it displaces a volume of fluid equal to its own volume. This is known as Archimedes' principle. The weight of the fluid or the density of the fluid are not directly related to the displacement of the object. Therefore, the correct answer is "volume of fluid."
10.
A fish normally displaces its own
Correct Answer
C. Both of these
Explanation
A fish normally displaces both its own volume of water and its weight of water. When a fish is submerged in water, it pushes aside the water around it, causing the water to be displaced. The amount of water displaced is equal to the volume of the fish's body, which is its own volume of water. Additionally, the fish's weight is supported by the water, so it also displaces its weight of water. Therefore, both of these statements are true.
11.
Compared to the density of water, the density of a fish is
Correct Answer
C. The same.
Explanation
The density of a fish is the same as the density of water. This means that the fish is neither more dense nor less dense than water. Density is a measure of how much mass is packed into a given volume, and since fish live in water and are adapted to their aquatic environment, their density is similar to that of water.
12.
What is the buoyant force acting on a 10-ton ship floating in the ocean?
Correct Answer
B. 10 tons
Explanation
The buoyant force acting on a ship floating in the ocean is equal to the weight of the water displaced by the ship. According to Archimedes' principle, an object submerged in a fluid experiences an upward force equal to the weight of the fluid it displaces. Since the ship is floating, the buoyant force is equal to the weight of the ship, which is 10 tons in this case.
13.
What is the weight of water displaced by a 100-ton floating ship?
Correct Answer
B. 100 tons
Explanation
The weight of water displaced by a floating ship is equal to the weight of the ship itself. This is because of Archimedes' principle, which states that the buoyant force acting on an object submerged in a fluid is equal to the weight of the fluid displaced by the object. Since the ship is floating, it displaces an amount of water that is equal to its own weight, which is 100 tons in this case.
14.
When an object is partly or wholly immersed in a liquid, it is buoyed up
Correct Answer
B. By a force equal to the weight of liquid displaced.
Explanation
When an object is partly or wholly immersed in a liquid, it experiences an upward force called buoyancy. According to Archimedes' principle, the buoyant force acting on an object is equal to the weight of the liquid displaced by the object. This means that the object will be buoyed up by a force equal to the weight of the liquid it displaces. Therefore, the correct answer is "by a force equal to the weight of liquid displaced."
15.
The buoyant force on an object is least when the object is
Correct Answer
A. Partly submerged.
Explanation
When an object is partly submerged, only a portion of its volume is immersed in the fluid. The buoyant force is equal to the weight of the fluid displaced by the object. Since the object is not fully submerged, the volume of fluid displaced is less compared to when it is fully submerged. Therefore, the buoyant force on the object is least when it is partly submerged.
16.
The buoyant force on a rock is least when the rock is submerged
Correct Answer
D. Buoyant force does not depend on depth.
Explanation
The buoyant force on an object submerged in a fluid is equal to the weight of the fluid displaced by the object. This force is independent of the depth at which the object is submerged. Therefore, the buoyant force on a rock is the same regardless of whether it is near the surface, halfway to the bottom, or near the bottom.
17.
The reason a life jacket helps you float is
Correct Answer
E. The density of both you and the jacket together is less than your density alone.
Explanation
The correct answer is that the density of both you and the jacket together is less than your density alone. This means that when you wear a life jacket, the overall density of your body and the jacket combined is lower than the density of your body alone. This lower density allows you to float in water because the buoyant force exerted by the water is greater than the gravitational force pulling you down.
18.
Blood pressure is normally greater in your
Correct Answer
B. Feet.
Explanation
Blood pressure is normally greater in your feet. This is because blood has to work against gravity to flow from the heart to the feet, causing an increase in pressure. Additionally, the blood vessels in the feet are smaller and more constricted compared to other parts of the body, which further contributes to higher blood pressure in the feet.
19.
When holes are drilled through the wall of a water tower , water will spurt out the greatest horizontal distance from the hole closest to
Correct Answer
A. The bottom of the tower.
Explanation
When holes are drilled through the wall of a water tower, water will spurt out the greatest horizontal distance from the hole closest to the bottom of the tower. This is because the water pressure is highest at the bottom of the tower due to the weight of the water above it. As a result, the water will be forced out with more force and will travel a greater horizontal distance compared to the holes at the middle or top of the tower where the water pressure is lower. Therefore, the hole closest to the bottom of the tower will have the greatest horizontal spurt distance.
20.
Lobsters live on the bottom of the ocean. The density of a lobster is
Correct Answer
A. Greater than the density of sea water.
Explanation
The correct answer is greater than the density of sea water. This is because lobsters have a higher density than sea water, which allows them to sink and live on the bottom of the ocean.
21.
A lobster crawls onto a bathroom scale submerged at the bottom of the ocean. Compared to its weight above the surface, the lobster will have an apparent weight under water that is
Correct Answer
B. Less.
Explanation
When the lobster is submerged in water, it experiences an upward buoyant force that counteracts its weight. This is because the density of the lobster is greater than the density of water. As a result, the lobster will feel lighter or have a lesser apparent weight under water compared to its weight above the surface.
22.
Two life preservers have identical volumes, but one is filled with Styrofoam while the other is filled with sand. When the two life preservers are fully submerged, the buoyant force is greater on the one filled with
Correct Answer
C. Same on each as long as their volumes are the same
Explanation
The buoyant force on an object is equal to the weight of the fluid it displaces. Since the two life preservers have identical volumes, they displace the same amount of fluid. Therefore, the buoyant force on each life preserver is the same as long as their volumes are the same.
23.
The density of a submerged submarine is about the same as the density of
Correct Answer
D. Water.
Explanation
A submerged submarine has a density that is about the same as water because it is designed to be neutrally buoyant. This means that the submarine is able to float and sink in water without any significant changes in its density. If the density of the submarine was higher than water, it would sink, and if it was lower, it would float to the surface. Therefore, the density of a submerged submarine is about the same as water.
24.
A rock suspended by a string weighs 5 N out of water and 3 N when submerged. What is the buoyant force on the rock?
Correct Answer
D. 2 N
Explanation
When the rock is submerged in water, it experiences a buoyant force that opposes its weight. The difference between the weight of the rock in air (5 N) and the weight of the rock in water (3 N) is equal to the buoyant force acting on the rock. Therefore, the buoyant force on the rock is 5 N - 3 N = 2 N.
25.
An egg is placed at the bottom of a bowl filled with water. Salt is slowly added to the water until the egg rises and floats. From this experiment, one concludes
Correct Answer
B. The density of salt water exceeds the density of egg.
Explanation
The correct answer is that the density of salt water exceeds the density of the egg. When salt is added to the water, it increases the density of the water. As a result, the density of the salt water becomes higher than the density of the egg, causing the egg to float. This experiment demonstrates the concept of buoyancy, where an object will float in a fluid if its density is lower than the density of the fluid it is placed in.
26.
Ice cubes submerged at the bottom of a liquid indicate that the liquid
Correct Answer
E. Is less dense than ice.
Explanation
When ice cubes are submerged at the bottom of a liquid, it indicates that the liquid is less dense than ice. This is because objects float in a liquid when the liquid is denser than the object. Since the ice cubes sink to the bottom, it means that the liquid is not displacing them, which suggests that the liquid has a lower density than the ice.
27.
A block of wood weighing 5 N in air, is difficult to fully submerge in a pool of mercury because the buoyant force when fully submerged is
Correct Answer
C. Much more than 5 N.
Explanation
When an object is submerged in a fluid, it experiences an upward force called the buoyant force. This force is equal to the weight of the fluid displaced by the object. In this case, the block of wood weighs 5 N in air, but when fully submerged in mercury, it displaces a volume of mercury that weighs much more than 5 N. Therefore, the buoyant force exerted on the block of wood is much more than 5 N, making it difficult to fully submerge the block of wood in the pool of mercury.
28.
The volume of water displaced by a floating 20-ton boat
Correct Answer
B. Is the volume of 20 tons of water.
Explanation
The correct answer is "is the volume of 20 tons of water." When a boat floats, it displaces an amount of water equal to its own weight. Since the boat weighs 20 tons, it displaces 20 tons of water, which is equivalent to a volume of 20 cubic meters.
29.
Compared to an empty ship, the same ship loaded with Styrofoam will float
Correct Answer
B. Lower in the water.
Explanation
When a ship is loaded with Styrofoam, it increases the overall weight of the ship. As a result, the ship will displace less water, causing it to sink lower in the water. This is because the buoyant force acting on the ship is now less than the weight of the ship, leading to a lower position in the water.
30.
Two equal sized buckets are filled to the top with water. One of the buckets has a piece of wood floating in it, making its total weight
Correct Answer
B. Equal to the weight of the other bucket.
Explanation
The piece of wood floating in the bucket does not affect the weight of the water in the bucket. The weight of the water in both buckets is the same because they are filled to the top. Therefore, the weight of the bucket with the piece of wood is equal to the weight of the other bucket.
31.
A block of Styrofoam floats on water while a same size block of lead lies submerged in the water. The buoyant force is greatest on the
Correct Answer
A. Lead.
Explanation
The buoyant force is the force exerted by a fluid on an object immersed in it. It is equal to the weight of the fluid displaced by the object. In this case, the block of Styrofoam floats on water because it is less dense than water and displaces a larger volume of water, resulting in a greater buoyant force. On the other hand, the block of lead is denser than water and displaces a smaller volume of water, leading to a smaller buoyant force. Therefore, the buoyant force is greatest on the lead block.
32.
A liter-sized block of ordinary wood floats in water. The amount of water displaced is
Correct Answer
A. Less than 1 liter.
Explanation
When a liter-sized block of ordinary wood is placed in water, it displaces a volume of water equal to its own volume. However, since wood is less dense than water, it weighs less than an equivalent volume of water. As a result, the amount of water displaced by the wood block is less than 1 liter.
33.
Buoyant force is greatest on a submerged
Correct Answer
B. 1-kg block of aluminum.
Explanation
The buoyant force experienced by an object submerged in a fluid depends on the density of the object and the density of the fluid. The buoyant force is equal to the weight of the fluid displaced by the object. Since the density of lead is greater than the density of aluminum, the 1-kg block of lead will displace less fluid than the 1-kg block of aluminum. Therefore, the buoyant force on the block of aluminum will be greater than the buoyant force on the block of lead.
34.
Buoyant force is greatest on a submerged
Correct Answer
C. Is the same on each
Explanation
The buoyant force experienced by an object submerged in a fluid is equal to the weight of the fluid displaced by the object. Since the volume of the object is the same (1 cubic centimeter) in both cases, the buoyant force will be the same for both the block of lead and the block of aluminum. The buoyant force is not dependent on the material of the object, but rather on the volume of fluid displaced.
35.
Buoyant force is greatest on a submerged
Correct Answer
B. 10-newton block of aluminum.
Explanation
The buoyant force experienced by an object submerged in a fluid is equal to the weight of the fluid displaced by the object. Since both the lead and aluminum blocks have the same volume, they displace the same amount of fluid. However, the weight of the aluminum block is less than the weight of the lead block. Therefore, the buoyant force on the aluminum block is greater, as it is more buoyant compared to the lead block.
36.
When you float in fresh water, the buoyant force that acts on you is equal to your weight. When you float higher in the high-density water of the Dead Sea, the buoyant force that acts on you is
Correct Answer
C. Equal to your weight.
Explanation
When you float in water, the buoyant force that acts on you is equal to the weight of the water displaced by your body. In fresh water, the density is lower compared to the high-density water of the Dead Sea. However, the buoyant force is still equal to your weight in both cases because the volume of water displaced by your body is the same. Therefore, the buoyant force in the high-density water of the Dead Sea is equal to your weight.
37.
Compared to the buoyant force that acts on you when you float in fresh water, the buoyant force that acts on you when you float in the dense water of the Dead Sea is
Correct Answer
C. The same.
Explanation
The buoyant force that acts on an object is equal to the weight of the fluid displaced by the object. When floating, the object displaces its own weight in fluid. In both fresh water and the dense water of the Dead Sea, the weight of the fluid displaced is the same, so the buoyant force is also the same. The buoyant force does not depend on the density of the fluid or the volume of the object being displaced.
38.
Two life preservers have identical volumes, but one is filled with Styrofoam while the other is filled with sand. When the two life preservers are worn by swimmers so that one swimmer floats with part of the preserver above water, and the other swimmer sinks, the buoyant force is actually greater on the life preserver filled with
Correct Answer
B. Sand.
Explanation
The buoyant force experienced by an object immersed in a fluid is equal to the weight of the fluid displaced by the object. Since the two life preservers have identical volumes, they will displace the same amount of water. However, the weight of the sand-filled life preserver is greater than the weight of the Styrofoam-filled life preserver. Therefore, the buoyant force acting on the sand-filled life preserver will be greater, causing it to sink while the Styrofoam-filled life preserver floats.
39.
A heavy glass ball is placed in a pie pan that floats in a bucket. The water level at the side of the bucket is marked. Then the glass ball is removed and allowed to sink in the bucket. The water line at the side of the bucket is now
Correct Answer
A. Lower.
Explanation
When the heavy glass ball is placed in the pie pan, it displaces a certain volume of water and causes the water level to rise. However, when the glass ball is removed and allowed to sink in the bucket, it displaces an even larger volume of water. This causes the water level to decrease, resulting in a lower water line at the side of the bucket.
40.
A boat loaded with scrap iron floats in a swimming pool. When the iron is thrown overboard, the pool level will
Correct Answer
B. Fall.
Explanation
When the boat is loaded with scrap iron, it displaces an amount of water equal to its weight, causing the pool level to rise. However, when the iron is thrown overboard, the weight of the boat decreases, resulting in less water being displaced. As a result, the pool level will fall.
41.
A row boat containing a barrel of water floats in a swimming pool. When the water in the barrel is poured overboard, the swimming pool level will
Correct Answer
C. Remain unchanged.
Explanation
When the water in the barrel is poured overboard, the water level in the swimming pool will remain unchanged. This is because the weight of the water in the barrel is equal to the weight of the water it displaces in the pool. When the water is poured out, the weight of the barrel decreases, but the weight of the water it displaces also decreases by the same amount. Therefore, the overall weight in the pool remains the same, resulting in no change in the water level.
42.
A boat loaded with wood floats in a swimming pool. When the wood is thrown overboard, the pool level will
Correct Answer
C. Remain unchanged.
Explanation
When the wood is thrown overboard, the pool level will remain unchanged. This is because the weight of the wood is equal to the weight of the water it displaces. When the wood is removed from the boat and thrown into the pool, it will displace an equal volume of water, causing the pool level to remain the same.
43.
If a battleship sinks in a canal lock, the water level in the lock will
Correct Answer
B. Fall.
Explanation
When a battleship sinks in a canal lock, it displaces a certain volume of water, causing the water level in the lock to decrease. This is because the volume of the battleship is now filled with water, which reduces the overall volume of the lock. Consequently, the water level falls as a result of the sinking battleship.
44.
When a boat sails from fresh water to salt water, the boat will float
Correct Answer
B. Higher in the water.
Explanation
When a boat sails from fresh water to salt water, the boat will float higher in the water. This is because salt water is denser than fresh water. The increased density of salt water provides more buoyancy to the boat, causing it to float higher.
45.
If the part of an iceberg that extends above the water were suddenly removed, the
Correct Answer
B. Buoyant force on the iceberg would decrease.
Explanation
When the part of an iceberg that extends above the water is suddenly removed, the buoyant force on the iceberg would decrease. This is because the buoyant force is the upward force exerted on an object immersed in a fluid, and it is equal to the weight of the fluid displaced by the object. The part of the iceberg above the water contributes to the buoyant force, so removing it would decrease the overall buoyant force acting on the iceberg. As a result, the iceberg would sink further into the water.
46.
If a weighted air-filled balloon sinks in deep water, it will
Correct Answer
D. Be acted on by a continuously decreasing buoyant force.
Explanation
As the weighted air-filled balloon sinks in deep water, it will experience a buoyant force acting against it. This buoyant force is caused by the difference in density between the balloon and the surrounding water. However, as the balloon sinks deeper, the water pressure increases, causing the air inside the balloon to compress. This compression decreases the volume of the balloon, making it less buoyant. Therefore, the buoyant force acting on the balloon will continuously decrease as it sinks, eventually causing it to sink to an equilibrium level where the buoyant force equals the weight of the balloon.
47.
When an ice cube in a glass of water melts, the water level
Correct Answer
C. Remains the same.
Explanation
When an ice cube melts in a glass of water, the ice cube turns into liquid water, but the total volume of water in the glass remains the same. This is because the ice cube displaces its own volume of water, and when it melts, it fills the space it previously occupied. Therefore, the water level in the glass remains unchanged.
48.
A floating ice cube contains small pieces of iron. During melting the water level will
Correct Answer
B. Fall.
Explanation
When the ice cube melts, the water level will fall. This is because the ice cube displaces a certain volume of water equal to its own volume. As the ice cube melts, it turns into liquid water, which takes up less space than the solid ice. Therefore, the water level will decrease as the ice cube melts and the water is no longer being displaced by the solid ice.
49.
An ice cube floating in a glass of water contains many air bubbles. When the ice melts, the water level will
Correct Answer
C. Remain unchanged.
Explanation
When an ice cube floats in water, it displaces its own weight in water due to Archimedes' principle. The ice cube contains air bubbles that contribute to its buoyancy. As the ice cube melts, it turns into liquid water, which has the same density as the surrounding water. Since the melted water has the same density as the water it is in, there is no additional volume added to the glass. Therefore, the water level will remain unchanged.
50.
Three icebergs are each floating in bathtubs filled to the brim with water. Iceberg A has large air bubbles in it. Iceberg B has unfrozen water in it. Iceberg C has an iron railroad spike in it. When the ice melts, what happens?
Correct Answer
A. The water level in C will decrease while the other two water levels will remain the same.
Explanation
When ice melts, it turns into water. Iceberg A, which has large air bubbles in it, will melt and the air bubbles will escape into the atmosphere, causing the water level to remain the same. Iceberg B, which has unfrozen water in it, will also melt and turn into water, but since it was already filled to the brim, the water level will remain the same. Iceberg C, which has an iron railroad spike in it, will melt and the water level will decrease as the iron spike takes up less space than the ice. Therefore, the water level in C will decrease while the water levels in A and B will remain the same.