Jump to content
BrainDen.com - Brain Teasers

BMAD

Members
  • Posts

    2213
  • Joined

  • Last visited

  • Days Won

    74

Everything posted by BMAD

  1. Mentally draw a line that connects the horns of a crescent moon and then extend this line down to the horizon. In northern latitudes this will give an approximate indication of south. It works best when the moon is high in the sky and not too near the horizon, when significant errors are possible. The reason this method works is not very complex. The sun and moon move across the sky in an east-west plane. In other words when they are not aligned (a new moon) then they are roughly either east or west of each other. Since the moon reflects the sun’s light, its bright side will be ‘pointing’ to the direction of the sun, ie. approximately east or west. The line that joins the horns of a crescent moon together is at right-angles to this east/west line and any line that is perpendicular to an east/west line must be a south/north line. If accuracy is needed, then there is only one method that can be used with the moon, but be warned it is not fast and can seriously dent your sleeping time. All celestial objects – sun, stars, planets and moon – arc across the southern sky when viewed from northern latitudes. They all reach their highest point in the sky when they cross your meridian or line of longitude and this will occur when they are exactly due south of you. In other words the moon will be highest in the sky when it is due south from the UK. The best way of working out when a bright object is at its highest point in the sky is by watching and marking shadow tips. It does not need to be a full moon, only a moon that is bright enough to cast a shadow. The curve that joins the tips of the shadow over an evening will make clear when the shadow is shortest and this will be a perfect north-south line. The moon will of course rise and set very roughly in the east and west, but working out exactly what direction the moon is rising or setting is fiendishly complex. There are some simple rules worth knowing. For example, a full moon will behave in the opposite way to the sun, in the UK it rises close to southeast in midsummer and northeast in midwinter, setting southwest in midsummer and northwest in midwinter. Taken from: http://www.naturalnavigator.com/find-your-way-using/moon
  2. It does, but I am reading by clock and not the sun.
  3. Diane grow leeks, Alec and Lisa grow carrots and Jacob and Chloe grow beans. Do Tom and Andrea grow courgettes or marrows?
  4. Hmmm i have a different answer. Can you explain yours so i can see my mistake. the owner of the jet ski can anchor it how they like
  5. John and Mary have fallen in love. John wants to send Mary a ring through the post but in their country of Kleptopia, any package that is not locked will have its contents stolen. John and Mary have plenty of padlocks but neither has the other's key. How can John get the ring safely to Mary?
  6. Thanks to a set of temporary magical powers you are in the final of the Wimbledon tennis championships up against seven-time winner Roger Federer. Your powers cannot last for the whole match and you must therefore choose the optimum time for them to run out. What is the score that gives you the maximum chance of winning?
  7. Angrily the guard walks to a table and shoves a black flask into your hand, "Drink". Not sure what else to do, you drink the foul smelling fluid. Your insides burn and twist in agony. You lose consciousness... Sometime later, you awake. Your stomach, no longer empty, gives you some respite but your muscles are terribly sore. For the first time you take stock of the room. Along the far wall. You see a burning fire pit with a long dirty wooden table in front of it. On the other two walls are two sleeping prisoners just like yourself. Upon the three of each of you is a bright yellow tunic, a silly thing you believe since the dark room makes the color virtually pointless. You scratch your face to satisfy an itch, which brings you a wonderful conclusion...your left arm is still free. You attempt to pull your right arm free but it is too tight. You look at the device holding your hand and realize that this shackle is different than the one the guard unlocked. It has a computer interface (command prompt) on it with a keypad for its user. On the opposite side of the shackle, you notice that someone etched a note...the password is utopia...
  8. Could we write the depth as a function of the rope and given information?
  9. It doesn't have to be Straight just continuous
  10. I am unsure what one would call this kind of meta puzzle in English but essentially this thread will contain a progression of mini puzzles centered around a protagonist (you) attempting to escape a dungeon. A new question will emerge, thus furthering the story, with a satisfying resolution to the current dilemna. ...enjoy! You awake to find that you are trapped in a dungeon. Chained to a wall, you see a guard in the corner. The guard approaches you. He takes a piece of chalk from his pocket and draws the Roman numeral for 9 on the wall next to you. He uncuffs your left wrist and hands you the chalk. "If you want food and drink, make this 9 a 6 adding only one line." At the mention of food, your belly churns and squeezes, "how long has it been since i've eaten?", you ask yourself. The guard stares at you with a foolish grin...
  11. Danny, who wasn't quite awake when he took his jet ski out on a lake, forgot to untie his jet ski from its anchor. As soon as he got to the end of the rope, the ski stopped sending Danny flying. The jet ski, which thankfully was in the middle of the lake, continued to go in circles from this point at a speed of 20 miles per hour. After six hours, the jet ski made 12 laps. How deep is the anchor?
  12. Were the marbles we picked from the jar randomly chosen?
  13. it would seem that this logic relies on the idea that each bullet's speed is distinct. Wouldn't bullets of the same speed add to the sample space, affecting the number of escape situations?
  14. So in environment one The rate of change of x is determined by both 2x and the interaction of -3xy What does this mean? Well it means that the species has a natural growth rate (i.e. the 2x represents the mating and therefore growth of the population) However the interaction of -3xy shows that as there are more y's, the overall growth of the species begins to go down. Hence this would imply that either the species y in this case is living off of the animal x or that y out competes x for the same food source. Looking at y's rate of change in this environment should clarify which of these two concepts are occurring.
  15. lol, forgot the statement: The difference between body temperature and the room temperature changes at a rate proportional to that difference.
  16. We have three separate environments where X and Y are unique species to each environment. Decide and justify what type of relationship the two respective species have in each environment. Environment 1 x' = 2x - 3xy y' = -3y + 4xy Environment 2 x' = xy - 2x y' = y - 2x Environment 3 x' = y y' = 1/x
  17. Consider this a differential equation problem.
  18. On the right track but I have a different time.
  19. assume in this case that it doesn't matter
  20. 2 very simple choices a killer could do if they wanted to confuse the detectives.
  21. Suppose that you come into your professor's office to ask some questions shortly before 9:00 a.m. on Friday. You find him lying on the floor of his office in a pool of chalk dust, dead. You quickly call the police and their investigators take several measurements over the next hour, including: 1) the body temperature at 9:00 a.m. - 80 degrees 2) the body temperature at 10:00 a.m. - 78 degrees 3) room temperature - 70 degrees (constant) You quickly realize that the police believe you to be a prime suspect, so you need an alibi. You know that you were studying until midnight, prove your innocence or go to jail.
×
×
  • Create New...