The bottom of a wheel never moves backwards if the wheel is rotating forwards. I've forgotten the name of the curve drawn but it's generated by x = t - sin(t), y = 1-cos(t). EDIT: The flange would be moving backwards at the very bottom in a train wheel though.
In grade 12 physics (final year) we had a book full of odd questions to solve. One of them went like this: (I don't remember the values so just grab some out of thin air...) A man hangs a boy from a tree by a rope. The boy weighs x amount of lbs. The rope is x amount of feet long. The man stands x feet away. He raises a bow and applies x amount of force to an arrow that weighs x amount of lbs. The arrow hits the body in the chest, how high does the body swing? I may of left out some details, but the book was just full of questions that were messed like that one.
A man jumps. A man who is twice as large in every dimension jumps. All else equal, how much higher does the bigger man jump? (this was an interview question I was asked to answer)
Oxford and Cambridge interviews are lame. Come on guys, man on horseback problem, nobody has gotten the correct answer yet!
I'm sure you need to give us a speed or time value in order to work out the distance travelled no? You can't work out distance travelled without one of those too values. Otherwise it can only be given in terms of x. 100/2x + 100/4x = 75/x =t time taken (x being speed in m/s) then distance travelled = tx
I'm a bit thick and can't add up. I reckon 33.3m on the way up and 25 m on the way back so I agree with EvilMerc.
Bungletron has the correct answer. It is 75m. Figure it this way. The time it takes him to move to the front of the coloumn is: X The time it takes him to move to the back of the coloumn is: Y The speed at which the officer moves is: Z This gives us the equation for the first journey to the front of the coloumn: ZX+100m=3ZX Eliminate one ZX 100m=2ZX Divide by two 50m=ZX Given that his relative speed is greater for the second part of his round trip, we get the following equation: 4ZY=100m Divide by four: ZY=25m Distance travelled = Z(X+Y) Distance travelled = ZX+ZY Distance travelled = 50m+25m Distance travelled = 75m QED
yeah that's right.. actually would have said 58.333 just thinking about it quickly but you have to count forward progress on the horses journey.. the speed of the brigade doesn't matter- it could vary as long as the the horse is travelling at 3x the speed so it will always be 75m from the from to the back.. so can we post up our own problems? ok here's one that will mystify (even me) if malvio gets a massage at 12 in the afternoon but then goes into a gay bar later that day and orders 2 drinks and only gets one drink.. how many roid rages would he have to do as a strait man to get his second drink WITHOUT getting a questionable massage.. and if supermonkey was in the bar- how many cups of tea would he have to drink to count as a good teabagging? sorry couldn't refrain from posting but first person to correctly answer this and my gaydar goes off fully.. gets a slap in the face!
Maths is much easier than psychology, and you got it right the first time. Some of you guys aren't taking into account the extra distance on the officer's foward trip, it's not 100m It's 100m + the distance moved by the troupe at 1/3 speed, and on the return trip, it's 100m - the exact same distance. (yes we are assuming all accelerations are instant) I made the same mistake initialy, the 100m point is not a fixed marker, it's moving at the speed it is when the officer returns, so the differences in distances will cancel out. The officer only travels a total of 200m! The troupe are moving at 1/3 speed, so no matter what speed the officer moves, if the troupe move at exactly 1/3 speed, they travel 66.666666m when the officer completes the trips. Maybe we should make things interesting... anyone up for betting a GTX460 on their answers?
lol sure I'd take that bet.. but I won't take your 460 mv your not taking into account the distance moved by the brigade while the horse is traveling.. it's 50 forward and 25 back.. simple really- the part where it gets confusing- like when first thought about it.. forgot the distance forward- so it's not 33.3 keep your 460 man.. I'm saving you from yourself =]
Try it out, lets say the troupe move at 1 meter per second, officer travels at 3/ms. If they travel 75m total, then the officer has travelled 225 meters.
the officer will travel at twice the speed forward, and 4x backwards.. at 1mps or 100mps he will always end up at the back of the line when the brigade hits 75m
