Guest Posted January 18, 2011 Report Share Posted January 18, 2011 A man weighing 40 kg wants to cross the river with 3 balls each weighing 5 kg there is only 1 boat which can carry upto 50 kg how can the man cross the river there is no bridge to cross the river. Quote Link to comment Share on other sites More sharing options...
0 curr3nt Posted January 18, 2011 Report Share Posted January 18, 2011 A man weighing 40 kg wants to cross the river with 3 balls each weighing 5 kg there is only 1 boat which can carry upto 50 kg how can the man cross the river there is no bridge to cross the river. He could take multiple trips or if it needs to be one crossing he could place the balls in the boat and swim the boat across. Quote Link to comment Share on other sites More sharing options...
0 Aaryan Posted January 18, 2011 Report Share Posted January 18, 2011 (edited) he is a juggler. But curr3nt could be right. you need to be more specific. Edited January 18, 2011 by Aaryan Quote Link to comment Share on other sites More sharing options...
0 Quantum.Mechanic Posted January 18, 2011 Report Share Posted January 18, 2011 He puts them in a bag, ties a long rope on it, and drags them across the bottom of the river. If it turns out they float, so much the better. 15Kg is not much of an anchor. Hopefully he has a motorboat, and a slow river. How wide is the river? He could shot put them over, a la George Washington. Or just pay $110 each, and have them delivered overnight to the other side. Seems a bit of a waste to send them all the way to Memphis and back, but at least they won't get wet. Quote Link to comment Share on other sites More sharing options...
0 Guest Posted January 18, 2011 Report Share Posted January 18, 2011 If together they displace 5kg of water, he could hold them in the water as he crosses Quote Link to comment Share on other sites More sharing options...
0 Guest Posted January 18, 2011 Report Share Posted January 18, 2011 He could go on a diet? Quote Link to comment Share on other sites More sharing options...
0 Guest Posted January 18, 2011 Report Share Posted January 18, 2011 he can put one ball in the water and push it along next to the boat. Quote Link to comment Share on other sites More sharing options...
0 Guest Posted January 18, 2011 Report Share Posted January 18, 2011 Please be more specific about these three, five kilogram orbs. Quote Link to comment Share on other sites More sharing options...
0 Guest Posted January 18, 2011 Report Share Posted January 18, 2011 A man weighing 40 kg wants to cross the river with 3 balls each weighing 5 kg there is only 1 boat which can carry upto 50 kg how can the man cross the river there is no bridge to cross the river. It doesn't say that he needs to do it in one trip so one way would be to take the balls across the river one or two at a time Quote Link to comment Share on other sites More sharing options...
0 Guest Posted January 18, 2011 Report Share Posted January 18, 2011 (edited) I think taking the question with a few parameters would help. Let's assume he can't swim as that defeats the whole idea of getting across using the boat, and further let's assume that a 5kg ball doesn't float lol and that only one trip is allowed as that too would be far too easy. Then I guess the first answer nailed it pretty well. He's a juggler, by juggling the balls one would always be in the air thus only 50kg would ever be on the boat at a time. Of course any juggler will tell you that by tossing and catching the ball the weight displaced would be considerably less than the 5kg needed to stay within the 50kg limit, but that's more physics than logic... did i just say that? lol Edited January 18, 2011 by Sardic Quote Link to comment Share on other sites More sharing options...
0 Guest Posted January 18, 2011 Report Share Posted January 18, 2011 A man weighing 40 kg wants to cross the river with 3 balls each weighing 5 kg there is only 1 boat which can carry upto 50 kg how can the man cross the river there is no bridge to cross the river. A man with 3 balls weighing 5 kgs each needs to see a doctor instead of crossing rivers! Quote Link to comment Share on other sites More sharing options...
0 Guest Posted January 19, 2011 Report Share Posted January 19, 2011 not sure about this but he might be able to save weight by somehow holding all three underwater. isn't it easier to lift heavy stuff underwater? don't know if its the 5 kg he needs though. lol to the previous post Quote Link to comment Share on other sites More sharing options...
0 Guest Posted January 19, 2011 Report Share Posted January 19, 2011 Not my strong suit but here goes: You could do this using the displacement method (carrying the balls submerged) as long as the balls are the same size and have a radius of at least 7.35506 cm. Assumptions: Water is 4 degrees C where 1 L = 1 Kg All three balls are the same size All three balls are spheres (not football/rugby shaped) To save 5 kg you have to displace 5 liters of water. Therefore each ball must displace 1.6666 liters. Following the formula to determine radius of a sphere from the volume "r = cuberoot(3V / 4Ï€)" you end up with 7.35506 cm. Quote Link to comment Share on other sites More sharing options...
0 Guest Posted January 19, 2011 Report Share Posted January 19, 2011 Tie 'em 3 balls and let 'em float, if they sink drag 'em under water or on the bottom surface. Hope his balls aren't too sensitive But I do hope he's got a doctor on the other side to have a look at his 3 balls Quote Link to comment Share on other sites More sharing options...
0 random7 Posted January 19, 2011 Report Share Posted January 19, 2011 A man weighing 40 kg wants to cross the river with 3 balls each weighing 5 kg there is only 1 boat which can carry upto 50 kg how can the man cross the river there is no bridge to cross the river. If it happens to be that two of the balls are in fact his own balls, then their weight would be included in the 40kg weight of the man. That is, he weights 30kg if you were to exclude the 5kg weight of each of his balls. If this is the case, then the man has one ball weighing 5kg, which takes the total weight to 45kg, which is low enough for him to row the boat across the river. Quote Link to comment Share on other sites More sharing options...
0 Guest Posted January 19, 2011 Report Share Posted January 19, 2011 I think taking the question with a few parameters would help. Let's assume he can't swim as that defeats the whole idea of getting across using the boat, and further let's assume that a 5kg ball doesn't float lol and that only one trip is allowed as that too would be far too easy. Then I guess the first answer nailed it pretty well. He's a juggler, by juggling the balls one would always be in the air thus only 50kg would ever be on the boat at a time. Of course any juggler will tell you that by tossing and catching the ball the weight displaced would be considerably less than the 5kg needed to stay within the 50kg limit, but that's more physics than logic... did i just say that? lol he should FedEx the balls... Quote Link to comment Share on other sites More sharing options...
0 Guest Posted January 19, 2011 Report Share Posted January 19, 2011 (edited) Ah, but if he's a Juggler and he's doing what's been suggested, how does he propel the boat across the river? Edited January 19, 2011 by Southpaw_Pete Quote Link to comment Share on other sites More sharing options...
0 Guest Posted January 19, 2011 Report Share Posted January 19, 2011 I have a problem with the juggler thing, try juggling 5kg balls and see how long you last Quote Link to comment Share on other sites More sharing options...
0 Guest Posted January 19, 2011 Report Share Posted January 19, 2011 He could take multiple trips or if it needs to be one crossing he could place the balls in the boat and swim the boat across. no your answer is wrong but sorry i left one line in question he cannot swim and is allowed to use the boat once Quote Link to comment Share on other sites More sharing options...
0 Guest Posted January 19, 2011 Report Share Posted January 19, 2011 Ah, but if he's a Juggler and he's doing what's been suggested, how does he propel the boat across the river? Correct Quote Link to comment Share on other sites More sharing options...
0 dark_magician_92 Posted January 19, 2011 Report Share Posted January 19, 2011 A man weighing 40 kg wants to cross the river with 3 balls each weighing 5 kg there is only 1 boat which can carry upto 50 kg how can the man cross the river there is no bridge to cross the river. I agree with the answer but you shud have framed the question diffrently, like "how did he cross the river?" and "not how can he cross the river?". anyways keep posting, all d best! Quote Link to comment Share on other sites More sharing options...
0 Guest Posted January 19, 2011 Report Share Posted January 19, 2011 He could carry 2 balls to the other side and come back for the other one. You have to be very specific. Quote Link to comment Share on other sites More sharing options...
0 Guest Posted January 19, 2011 Report Share Posted January 19, 2011 A man weighing 40 kg wants to cross the river with 3 balls each weighing 5 kg there is only 1 boat which can carry upto 50 kg how can the man cross the river there is no bridge to cross the river. Float or drag the 15g balls in the water while the 40g man rows the boat across the river. Quote Link to comment Share on other sites More sharing options...
0 Guest Posted January 20, 2011 Report Share Posted January 20, 2011 when submerged under water weight become less, so he can carry by hanging those balls under boat.. Quote Link to comment Share on other sites More sharing options...
0 Quantum.Mechanic Posted January 20, 2011 Report Share Posted January 20, 2011 Correct The instantaneous weight (force) will be above the 50kg limit when he throws or catches each ball. What's supporting the balls in the air? Essentially, the force of the boat pushing against the water, transferred through the juggler. If this effect worked, someone would suggest that airplane passengers jump up and down during takeoff, to shorten the needed runway. And trust me, if this worked, the airlines would only buy airplanes with enough headroom to jump during takeoff. Quote Link to comment Share on other sites More sharing options...
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A man weighing 40 kg wants to cross the river with 3 balls each weighing 5 kg there is only 1 boat which can carry upto 50 kg how can the man cross the river there is no bridge to cross the river.
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