Cyberlounge Gym

Brain Exercisers

1. How far into the forest can a dog run?

2. What is the one word in the English language that is always pronounced incorrectly?

3. A boat has a ladder that has six rungs, each rung is one foot apart. The bottom rung is one foot from the water. The tide rises at 12 inches every 15 minutes. High tide peaks in one hour. When the tide is at it's highest, how many rungs are under water?

4. There is a house with four walls. Each wall faces south. There is a window in each wall. A bear walks by one of the windows. What color is the bear?

5. There is a room. The shutters are blowing in. There is broken glass on the floor. There is water on the floor. You find Sloppy dead on the floor. How did sloppy die?

6. How much dirt would be in a hole 6 feet deep and 6 feet wide that has been dug with a square edged shovel?

7. If I were in Hawaii and dropped a bowling ball in a bucket of water which is 45 degrees F, and dropped another ball of the same weight, mass, and size in a bucket at 30 degrees F, dropping them at the same time, which ball would hit the bottom of the bucket first?

8. What can go up a chimney down, but can't go down a chimney up?

9. If a farmer has 5 haystacks in one field and 4 haystacks in the other field, how many haystacks would he have if he combined them all in the center field?

10. What is it that goes up and goes down but does not move?

11. What has four legs but only one foot?

12. How many of each animal did Moses take on the ark?

13. If it takes 3 people to dig a hole, how many does it take to dig half a hole?

14. What is the beginning of eternity, the end of time and space, the beginning of every end, and the end of every place.

15. One morning as Paul was getting his newspaper, he noticed on his new house something that needed to be fixed. Heading over to the hardware store, he spoke to the manager, describing his problem. The manager said, "I know just what you need". He led Paul down some aisles and stopped in front of some bins. Digging down into some of the bins, he set something up on the shelf. "I saw your house when it was built", the manager said. "Here's all that you'll need and how much it'll cost... five will be 15 cents while fifty will be 30 cents, 250 will be 45 cents, while 2507 will only cost you 60 cents. One lady, about 20 blocks from your house, bought 30247 and only paid 75 cents! These are black, but they also come in gold and silver." What was the manager selling?

16. How long did the Hundred Years War last?

17. Which country makes Panama hats?

18. From which animal do we get catgut?

19. In which month do Russians celebrate the October Revolution?

20. What is a camel's hair brush made of?

21. The Canary Islands are named after what animal?

22. What was King George VI's first name?

23. What color is a purple finch?

24. Where are Chinese gooseberries from?

25. How long did the Thirty Years War last?

26. Two people are talking long distance on the phone; one is in an East-Coast state of the US, the other is in a West-Coast state of the US. The first asks the other "What time is it?", hears the answer, and says, "That's funny. It's the same time here!"

27. Why does a mirror appear to invert the left-right directions, but not up-down?

28. Two spheres are the same size and weight, but one is hollow. They are each made of uniform material, though of course not the same material. With a minimum of apparatus, how can I tell which is hollow?

29. Everyone knows that a shadow cast by the Sun changes during the day--it's longest at sunrise and sunset and shortest at noon. Is there a place on Earth where a shadow stays the same length all day long?

30. A Ping-Pong ball is tossed into the air. Will it take longer for it to go up or to come back down?

31. You have two large, opaque vessels. One contains kerosene, the other contains kerosene and water. How can you tell the one from the other using a spring scale and a weight on a string?

32. You put two pails of water outside on a freezing day. One has hot water (95 degrees C) and the other has an equal amount of colder water (50 degrees C). Which freezes first? Why?

33. Complete this letter sequence: _ T T F F S S _ _ T _ T T F F S S _

34. Complete this letter sequence: _ I _ G _ O _

Answers/Solutions

1. halfway. Beyond the halfway point, the dog will start to run out of the forest.
2. incorrectly
3. None, as the ladder is attached to the boat, it moves with the boat as the boat rises with the tide.
4. White. There is only one place in the world where all the walls can face south, and that is if the house is in the North Pole, the only type of bear found in the North Pole is a polar bear.
5. Sloppy is a goldfish, the wind blew the shutters open, knocking over the bowl, which fell to the ground and got smashed, and Sloppy was killed.
6. None, a hole has the dirt removed.
7. Water freezes at 32 degrees F, So, the bowling ball would have been stopped by the ice from reaching the bottom.
8. temperature.
9. One big haystack.
10. an umbrella.
11. a bed.
12. None, it was Noah who built the ark, not Moses.
13. It is impossible to have half a hole. Either you have one or not.
14. the letter 'e'
15. Number plates for addresses.
16. 116 years, from 1337 to 1453.
17. Ecuador.
18. From sheep and horses.
19. November. The Russian calendar was 13 days behind ours.
20. Squirrel fur.
21. The Latin name was Insularia Canaria - Island of the Dogs.
22. Albert. When he came to the throne in 1936 he respected the wish of Queen Victoria that no future king should ever be called Albert.
23. Distinctively crimson.
24. New Zealand.
25. Thirty years, of course. From 1618 to 1648.
26. One is in Eastern Oregon (in Mountain time), the other in Western Florida (in Central time), and it's daylight-savings changeover day at 1:30 AM.
27. Mirrors invert front to back, not left to right.

28. Since the balls have equal diameter and equal mass, their volume and density are also equal. However, the mass distribution is not equal, so they will have different moments of inertia - the hollow sphere has its mass concentrated at the outer edge, so its moment of inertia will be greater than the solid sphere. Applying a known torque and observing which sphere has the largest angular acceleration will determine which is which. An easy way to do this is to "race" the spheres down an inclined plane with enough friction to prevent the spheres from sliding. Then, by conservation of energy: mgh = 1/2 mv^2 + 1/2 Iw^2 Since the spheres are rolling without sliding, there is a relationship between velocity and angular velocity: w = v / r so mgh = 1/2 mv^2 + 1/2 I (v^2 / r^2) = 1/2 (m + I/r^2) v^2 and v^2 = 2mgh / (m + I / r^2) From this we can see that the sphere with larger moment of inertia (I) will have a smaller velocity when rolled from the same height, if mass and radius are equal with the other sphere. Thus the solid sphere will roll faster.

29. At the North and South poles, the Sun is at the same height all day long (except for their respective "polar nights," when the Sun doesn't shine at all). So the shadow of any object at the poles "walks around" the same spot all day, and its length stays the same.
30. The flying ball has to work against air resistance and thus continuously loses energy. So the total energy of the rising ball at a certain height is greater than that of the falling ball at the same height. Since the potential energy at these two moments is the same, the kinetic energy and, therefore, the speed of the ball at a certain height is greater when it rises than when it falls. So the time of descent is greater than the time of ascent.
31. Attach the string with the weight to the scale and lower the weight slowly into each of the vessels. In pure kerosene, the reading on the scale won't change as the weight goes down; but in the other vessel the reading will jump at the boundary between the two liquids: water is denser than kerosene, so the buoyant force increases abruptly at this point.
32. The hot water freezes first! It is commonly argued that the hot water will take some time to reach the initial temperature of the cold water, and then follow the same cooling curve. So it seems at first glance difficult to believe that the hot water freezes first. . The effect is definitely real and can be duplicated in your own kitchen. Every "proof" that hot water can't freeze faster assumes that the state of the water can be described by a single number. Remember that temperature is a function of position. There are also other factors besides temperature, such as motion of the water, gas content, etc. With these multiple parameters, any argument based on the hot water having to pass through the initial state of the cold water before reaching the freezing point will fall apart. The most important factor is evaporation. The cooling of pails without lids is partly Newtonian and partly by evaporation of the contents. The proportions depend on the walls and on temperature. At sufficiently high temperatures evaporation is more important. If equal masses of water are taken at two starting temperatures, more rapid evaporation from the hotter one may diminish its mass enough to compensate for the greater temperature range it must cover to reach freezing. The mass lost when cooling is by evaporation is not negligible. In one experiment, water cooling from 100C lost 16% of its mass by 0C, and lost a further 12% on freezing, for a total loss of 26%. The cooling effect of evaporation is twofold. First, mass is carried off so that less needs to be cooled from then on. Also, evaporation carries off the hottest molecules, lowering considerably the average kinetic energy of the molecules remaining. This is why "blowing on your soup" cools it. It encourages evaporation by removing the water vapor above the soup. Thus experiment and theory agree that hot water freezes faster than cold for sufficiently high starting temperatures, if the cooling is by evaporation. Cooling in a wooden pail or barrel is mostly by evaporation. In fact, a wooden bucket of water starting at 100C would finish freezing in 90% of the time taken by an equal volume starting at room temperature. The folklore on this matter may well have started a century or more ago when wooden pails were usual. Considerable heat is transferred through the sides of metal pails, and evaporation no longer dominates the cooling, so the belief is unlikely to have started from correct observations after metal pails became common.
33. One, Two, Three, Four, Five, Six, Seven, Eight, Nine, Ten, Eleven, Twelve, etc.
34. Violet, Indigo, Blue, Green, Yellow, Orange, Red, (visible spectrum of light)

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