Q&A Hero

Q: 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 A) Styrofoam. B) sand. C) same on each as long as their volumes are the same

Q: The reason a life jacket helps keep you afloat is A) the jacket makes you weigh less. B) the jacket has the same density as an average human. C) the jacket repels water. D) if you sink, the jacket sinks. E) the density of both you and the jacket together is less than your density alone.

Q: A 5-N block of wood is difficult to fully submerge in a pool of mercury because the buoyant force on the block when submerged is A) less than 5 N. B) 5 N. C) much more than 5 N.

Q: Ice cubes submerged at the bottom of a liquid indicate that the liquid A) produces insufficient buoyant force on the ice. B) is warmer than the ice. C) is only partly displaced by the submerged ice. D) is less dense than ice.

Q: An egg rests at the bottom of a bowl filled with water. When salt is slowly added to the water the egg rises and floats, from which we conclude A) salt water is denser than fresh water. B) salt water is denser than an egg. C) both of these D) neither of these

Q: The density of a submerged submarine at rest is about the same as the density of A) a crab. B) iron. C) a floating submarine. D) water. E) none of the above

Q: A lobster crawls onto a bathroom scale on the ocean floor. Its weight compared to its weight above the surface is A) greater. B) less. C) the same.

Q: Lobsters live on the bottom of the ocean, which means their density is A) greater than the density of sea water. B) equal to the density of sea water. C) less than the density of sea water.

Q: Compared to the density of water, the density of a fish is A) more. B) less. C) the same.

Q: A fish normally displaces its own A) volume of water. B) weight of water. C) both of these D) neither of these

Q: Pumice is a volcanic rock that floats, which means its density is A) less than the density of water. B) equal to the density of water. C) more than the density of water. D) need more information.

Q: A scale from which a rock is suspended reads 5 N when the rock is out of water and 3 N when the rock is submerged. The density of the rock is A) the density of water. B) 1.5 times the density of water. C) 2.5 times the density of water. D) 3.5 times the density of water. E) none of the above

Q: Buoyant force is greater on a submerged 10-newton block of A) lead. B) aluminum. C) same on each

Q: Buoyant force is greater on a submerged 1-cubic centimeter block of A) lead. B) aluminum. C) same on each

Q: Buoyant force is greater on a submerged A) 1-kg block of lead. B) 1-kg block of aluminum. C) is the same on each

Q: A scale from which a rock is suspended reads 5 N when the rock is out of water and 3 N when the rock is submerged. Buoyant force on the rock is A) 2 N. B) 3 N. C) 4 N. D) 5 N.

Q: What is the weight of water displaced by a 100-ton floating ship? A) less than 100 tons B) 100 tons C) more than 100 tons D) 100 cubic meters E) depends on the ship's shape

Q: When an object is partly or wholly immersed in a liquid, it is buoyed up A) by a force equal to its own weight. B) by a force equal to the weight of liquid displaced. C) and floats in accord with Archimedes' principle. D) all of the above E) none of the above

Q: A block of Styrofoam floats on water while a lead block of the same size block lies submerged in the water. The buoyant force is greatest on the A) lead. B) Styrofoam. C) same for both

Q: When a boat sails from fresh water to salt water, the boat will float A) lower in the water. B) higher in the water. C) at the same water level.

Q: The volume of water displaced by a floating 20-ton boat A) is 20 cubic meters. B) is the volume of 20 tons of water. C) is the volume of the boat. D) depends on the shape of the ship's hull. E) none of the above

Q: The buoyant force acting on a 10-ton ship floating in the ocean is A) less than 10 tons. B) 10 tons. C) more than 10 tons. D) depends on density of sea water

Q: The least buoyant force on a rock is when it is submerged A) near the surface. B) halfway to the bottom. C) near the bottom. D) none of the above

Q: The buoyant force on an object is least when the object is A) partly submerged. B) submerged near the surface. C) submerged near the bottom. D) none of the above

Q: A completely submerged object always displaces its own A) volume of fluid. B) weight of fluid. C) density of fluid. D) all of the above E) none of the above

Q: There is a legend of a Dutch boy who bravely held back the Atlantic Ocean by plugging a leak near the top of a dike with his finger until help arrived. Which is the more likely scenario? A) the huge size of the Atlantic Ocean makes this impossible B) although the force on his finger would have been huge, the pressure would have been small enough for this to occur C) the force on his finger would have been less than 1 N D) both force and pressure on his finger would have been great, but not too great for a public-spirited Dutch lad E) none of the above

Q: When holes are drilled through the wall of a water tower, water will spurt out with the greatest speed from the hole closest to A) the bottom of the tower. B) the middle of the tower. C) the top of the tower. D) all the same

Q: Buoyant force acts upward on a submerged object because A) it acts in a direction to oppose gravity. B) the weight of fluid displaced reacts with an upward force. C) pressure against its bottom is greater than pressure against its top. D) none of the above

Q: The mass of a cubic meter of water is A) 1 kg. B) 10 kg. C) 100 kg. D) 1000 kg. E) 9800 N.

Q: The pressure at the bottom of a jug filled with water does NOT depend on A) the acceleration due to gravity. B) water density. C) the height of the liquid. D) surface area of the water. E) none of the above

Q: The pressure in a liquid depends on liquid A) density. B) depth. C) both of these D) neither of these

Q: A dam is thicker at the bottom than at the top mainly because A) water is denser at deeper levels. B) water pressure increases with depth. C) surface tension exists only on the surface of liquids. D) it looks better. E) none of the above

Q: Water pressure on a submerged object is greatest against its A) top. B) bottom. C) sides. D) same against all surfaces E) none of the above

Q: While standing, your blood pressure is normally greatest in your A) head. B) heart. C) feet. D) same in each

Q: One liter of water has a mass of A) 1 kilogram. B) 14.7 grams. C) 500 grams. D) none of the above

Q: A hospital patient confined to bed will be less likely to develop bed sores with a A) firm mattress. B) soft mattress. C) water bed. D) none of these will help.

Q: Sara lies on a bed of sharp nails without harm because A) many of the nails don't make contact with her body. B) her weight is distributed over hundreds of nails. C) she exercises mind over matter. D) none of the above

Q: When you stand with only one of your feet on a weighing scale, the scale reading is A) half. B) the same as with both feet. C) doubled. D) none of the above

Q: Which will remain the same for two identical books, one lying flat and the other standing on an end? A) weight B) pressure C) both of these D) neither of these

Q: The concept of pressure involves both A) force and volume. B) force and area. C) area and volume.

Q: Consider the fictional case of the incredible shrinking woman. If a fictional shrinking woman shrinks to 0.1 her original height, her total skin area shrinks to A) 0.1 times its original value. B) 0.01 times its original value. C) 0.001 times its original value. D) 0.0001 times its original value. E) none of the above

Q: If a fictional shrinking man shrinks proportionately to 1/10 his original height, his weight will be multiplied by A) 0.1. B) 0.01. C) 0.001. D) 0.0001. E) none of the above

Q: The larger a turkey cooked in a conventional oven at a given temperature, the A) more time per pound is needed. B) less time per pound is needed. C) the same time per pound is needed.

Q: Eight little spheres of mercury coalesce to form a single sphere. Compared to the combined surface areas of the eight little spheres, the surface area of the big sphere is A) one eighth. B) one quarter. C) one half. D) the same. E) double.

Q: Eight little spheres of mercury coalesce to form a single sphere. Compared to the combined surface areas of the eight little spheres, the surface area of the big sphere is A) less. B) the same. C) greater.

Q: If you bake cupcakes as directed for a cake, the cupcakes will be A) over-baked. B) under-baked. C) properly baked.

Q: The effects of scaling are beneficial to swimmers in a race who are relatively A) large. B) small. C) neither of these

Q: Compared to a 50-kg person, a 100-kg person at the beach requires A) twice as much suntan lotion. B) the same amount of suntan lotion. C) less than twice as much suntan lotion.

Q: A solid glass ball weighs 1 N. One with twice the diameter weighs A) 1 N. B) 2 N. C) 3 N. D) 4 N. E) more than 4 N.

Q: Tripling the linear size of an object multiplies its area by A) 3 and its volume by 9. B) 9 and its volume by 18. C) 9 and its volume by 27. D) 27 and its volume by 81. E) none of the above

Q: If each dimension of a steel bridge is scaled up ten times, its strength will be multiplied by about A) ten and its weight by ten also. B) one hundred, and its weight by one thousand. C) one thousand, and its weight by one hundred thousand. D) none of the above

Q: In cold weather, your hands will be warmer if you wear A) gloves. B) mittens. C) both the same

Q: A dome-shaped house is more heat efficient than a rectangular house because a dome has A) no corners to radiate. B) less interior space. C) less area compared to its volume. D) all of the above E) none of the above

Q: When a living cell doubles in diameter, it has eight times the mass to be nourished, and the amount of membrane through which it feeds is A) only twice as much. B) only four times as much. C) also eight times as much. D) more than eight times as much.

Q: The effects of scaling are beneficial to small creatures A) that get wet. B) that fall from great heights. C) who are hungry. D) all of the above E) none of the above

Q: Which potato cooks faster in boiling oil? A) a whole potato. B) a sliced potato. C) both the same

Q: An elephant radiates less heat for its size than smaller animals because A) its radiating area is small compared to its volume. B) its radiating area is large compared to its volume. C) it is taller than smaller animals. D) it weighs more than smaller animals.

Q: If an elephant grows proportionally to twice its height, its weight would be multiplied by about A) 2. B) 4. C) 6. D) 8. E) none of the above

Q: If an elephant grows proportionally to twice its height, the area of its ears would be about A) twice. B) four times more. C) six times more. D) eight times more. E) none of the above

Q: To make taffy apples, a candymaker buys 100 kg of large apples rather than 100 kg of small apples. That means she will need A) less taffy. B) more taffy. C) the same amount of taffy.

Q: Suppose you put a chocolate layer on pieces of candy. Compared with the amount of chocolate used to cover 1 pound of large pieces, if you cover 1 pound of smaller pieces you'll use A) less chocolate. B) the same amount of chocolate. C) more chocolate. D) makes no difference

Q: Which potatoes when peeled produce the most peelings? A) 10 kg of large potatoes B) 10 kg of small potatoes C) both the same

Q: One kilogram of peaches has more skin area than one kilogram of A) blueberries. B) grapefruits. C) grapes. D) all of the above

Q: Doubling the linear size of an object multiplies its area by A) 2 and its volume by 4. B) 4 and its volume by 8. C) 8 and its volume by 16. D) none of the above

Q: The weight of a 1-centimer cubed metal cube scaled up by a factor of 10 will be A) ten times as much. B) a hundred times as much. C) a thousand times as much. D) none of the above

Q: A 1-centimeter cubed sugar cube scaled up by a factor of 10 has a total surface area of A) 60 cm2. B) 600 cm2. C) 6000 cm2. D) none of the above

Q: A 1-centimeter cubed sugar cube scaled up by a factor of 10 has a volume of A) 10 cm3. B) 100 cm3. C) 1000 cm3. D) none of the above

Q: If a pencil's length and diameter are both multiplied by 10, then its volume is multiplied by A) 10. B) 100. C) 1000. D) 10,000. E) none of the above

Q: A creature that is scaled up in size, keeping its proportions, A) will be stronger relative to its greater weight. B) will be weaker relative to its greater weight. C) both of these D) neither of these

Q: Lillian sees a chair at the Exploratorium that has been scaled up by three. In attempting to lift it, she finds the chair is A) three times as heavy. B) six times as heavy. C) nine times as heavy. D) more than nine times as heavy.

Q: Which geometrical shape has the least surface area for a given volume? A) cube B) pyramid C) cylinder D) sphere E) none of the above

Q: Flatten a spherical meatball into a hamburger and you increase its A) surface area. B) volume. C) both of these D) none of these

Q: Which has more skin compared to its body weight? A) an elephant B) a mouse C) both the same

Q: Which has more skin? A) an elephant B) a mouse C) both the same

Q: An athlete can perform a certain number of pushups. The same athlete scaled up in size can do A) fewer pushups. B) the same number of pushups. C) more pushups.

Q: The strength of a beam is most related to its A) cross section. B) length. C) both of these

Q: Support a horizontal toothpick at both ends. Then do likewise for a log of the same kind of wood. There is more sag in the A) toothpick. B) log. C) same in each

Q: A catenary in nature is evident in A) eggs. B) a necklace drooping between your fingers. C) the domes of some modern buildings. D) all of the above

Q: The Gateway Arch in St. Louis, Missouri, is a A) parabola. B) hyberbola. C) catenary.

Q: When the curve of a vertical structure matches the inverted image of a drooping chain held at both ends, the curve is called a A) parabola. B) hyperbola. C) catenary.