{"content":{"sharePage":{"page":0,"digests":[{"id":"24569323","dateCreated":"1274758415","smartDate":"May 24, 2010","userCreated":{"username":"sewzhentao","url":"https:\/\/www.wikispaces.com\/user\/view\/sewzhentao","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"},"monitored":false,"locked":false,"links":{"self":"https:\/\/vresolution.wikispaces.com\/share\/view\/24569323"},"dateDigested":1532092035,"startDate":null,"sharedType":"discussion","title":"Discussion (Andrew Tan, Joshua, Zhen Tao)","description":"Lets dicuss here","replyPages":[{"page":0,"digests":[{"id":"24569483","body":"I will start off with the definition. A vector is a quantity which has both magnitude and direction. Any vector directed at an angle to the horizontal (or the vertical) can be thought of as having two components.
\n
\nVector Resolution has two main topics
\n1)Parallelogram Method of Vector Resolution
\n2)Trigonometric Method of Vector Resolution","dateCreated":"1274759050","smartDate":"May 24, 2010","userCreated":{"username":"andrew-tan","url":"https:\/\/www.wikispaces.com\/user\/view\/andrew-tan","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"24569511","body":"I feel that the two straps actually help reduce the amount of tension on the rope and the climber in front. However, they should do the same for the life line connecting each climber instead of just using a rope","dateCreated":"1274759149","smartDate":"May 24, 2010","userCreated":{"username":"sewzhentao","url":"https:\/\/www.wikispaces.com\/user\/view\/sewzhentao","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"24569835","body":"I think that both guys are wrong. Anchor equalization is an important process in rock climbing and in normal circumstances, the anchors are placed close to each other at the same height.
\nAn unequalized anchor has been dubbed The American Death Triangle. It is not safe as it creates unnecessary strain on the fixed points.
\nThe percentage of rappel force placed on each of two fixed points can be calculated by the equation: 50% \u00f7 Cos(Anchor Angle \u00f7 Therefore at a smaller angle, the rappel force at both anchors are smaller.","dateCreated":"1274760059","smartDate":"May 24, 2010","userCreated":{"username":"andrew-tan","url":"https:\/\/www.wikispaces.com\/user\/view\/andrew-tan","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"24569905","body":"equations I have found to calculate rappel force: 50% \u00f7 Cos(Anchor Angle \u00f7 2)
\n F(anchor) = F(load)\/2cos(\u03b8\/2)","dateCreated":"1274760271","smartDate":"May 24, 2010","userCreated":{"username":"andrew-tan","url":"https:\/\/www.wikispaces.com\/user\/view\/andrew-tan","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"24570267","body":"Therefore, if we increase the number of straps, it should help reduce tension in the string.","dateCreated":"1274761519","smartDate":"May 24, 2010","userCreated":{"username":"sewzhentao","url":"https:\/\/www.wikispaces.com\/user\/view\/sewzhentao","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"24570295","body":"That is right? Right? I mean if the angle affects the amount of tension, by adding one more strap, it would reduce the amount of tension in each string. However, why does no one do that","dateCreated":"1274761609","smartDate":"May 24, 2010","userCreated":{"username":"sewzhentao","url":"https:\/\/www.wikispaces.com\/user\/view\/sewzhentao","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"24571495","body":"Well, I suppose that it is commonly agreed on an international basis that two is the required number for this type of anchoring. Increasing the number of straps is an interesting solution however, we need to take into consideration the structure of the harness as well as how it is connected to the anchor points and whether three is a feasible idea.","dateCreated":"1274767033","smartDate":"May 24, 2010","userCreated":{"username":"andrew-tan","url":"https:\/\/www.wikispaces.com\/user\/view\/andrew-tan","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"24626499","body":"Hmmm. Let me add in something.
\n
\nResponse to video:
\n1st comment: Anchor system is essential for rock climbing.
\n
\nReply: Definitely. Duhz.
\n
\n2nd comment: Yes. A good two point anchor system is one that has a large angle in between the two anchors.
\n
\nReply: For the two anchor points to be placed as far apart from each other as possible, it would be a little difficult.
\n
\n3rd comment: Well, I think a good two point anchor system is one which the two anchors are perpendicular to each other but the vertical positions of the two anchors are not on the same horizontal level.
\n
\nReply: Possibly.
\n
\n4th comment: Is it right to say anchor systems are safest when they equalize forces?
\n
\nReply: Yes, possibly.
\n
\nI feel that anchor systems are safest when they equalize forces.
\n- For the two anchor points to be able to support as much downwards force as possible, the two anchor points should be as close to each other as possible
\n- Thus the force can be distributed proportionally between two anchor points","dateCreated":"1274853561","smartDate":"May 25, 2010","userCreated":{"username":"wearestrong","url":"https:\/\/www.wikispaces.com\/user\/view\/wearestrong","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"24626503","body":"from Ivan btw.","dateCreated":"1274853575","smartDate":"May 25, 2010","userCreated":{"username":"wearestrong","url":"https:\/\/www.wikispaces.com\/user\/view\/wearestrong","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"24626505","body":"Ivan Mak Zhen Rong Ortus 4O1 (11)","dateCreated":"1274853600","smartDate":"May 25, 2010","userCreated":{"username":"wearestrong","url":"https:\/\/www.wikispaces.com\/user\/view\/wearestrong","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}}],"more":0}]},{"id":"24569175","dateCreated":"1274758094","smartDate":"May 24, 2010","userCreated":{"username":"twj","url":"https:\/\/www.wikispaces.com\/user\/view\/twj","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"},"monitored":false,"locked":false,"links":{"self":"https:\/\/vresolution.wikispaces.com\/share\/view\/24569175"},"dateDigested":1532092036,"startDate":null,"sharedType":"discussion","title":"Group Discussion (Members: Wei Jie , Nicholas)","description":"I disagree with Max that a good anchor system should have a large angle in between. The angle between the two anchors should be small, which would allow the anchor system to be able to withstand more weight. This would be safer for the climber as it will prevents accidents due to heavier weights.","replyPages":[{"page":0,"digests":[{"id":"24569403","body":"Yeah I agree with Wei Jie that the angle between the two angles should be rather small, prefably at 20\u00b0 apart where the load would be split evenly in which each anchor takes 50% load. If the angle increases, the weight distribution increases too, hence the need to keep the anchors not too far apart. As a general rule, the anchors should not be more than 90\u00b0 apart, so I would agree with Mark about the anchors being perpendicular to each other but it might not neccesarily make a good two-point anchor system.","dateCreated":"1274758753","smartDate":"May 24, 2010","userCreated":{"username":"SieNicholas","url":"https:\/\/www.wikispaces.com\/user\/view\/SieNicholas","imageUrl":"https:\/\/www.wikispaces.com\/user\/pic\/1246320799\/SieNicholas-lg.jpg"}}],"more":0}]},{"id":"24566119","dateCreated":"1274753258","smartDate":"May 24, 2010","userCreated":{"username":"Streetballz","url":"https:\/\/www.wikispaces.com\/user\/view\/Streetballz","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"},"monitored":false,"locked":false,"links":{"self":"https:\/\/vresolution.wikispaces.com\/share\/view\/24566119"},"dateDigested":1532092036,"startDate":null,"sharedType":"discussion","title":"Group Discussion (Mark Tay, Dennis Chu, Ng Qi Xiang)","description":"Is it right to say anchor systems are safest when they equalize forces?","replyPages":[{"page":0,"digests":[{"id":"24566751","body":"I feel that for a good two point anchor system, the angle in between the 2 anchors must be as small as possible. A smaller angle between the 2 anchors would give a greater resultant force. The smaller the angle between the 2 anchors,the anchor system can support a larger weight. therefore the angle must be small.","dateCreated":"1274754030","smartDate":"May 24, 2010","userCreated":{"username":"qixiang","url":"https:\/\/www.wikispaces.com\/user\/view\/qixiang","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"24567457","body":"Pertaining to the angle, I thinnk that the angle should be of a moderate size, not too small. This is because if the angle is too small, there is a lot of tension in both ropes if the person falls. Hence, if the angle is moderate, the system will be able to support the biggest weight with the least tension in the rope.","dateCreated":"1274755118","smartDate":"May 24, 2010","userCreated":{"username":"Streetballz","url":"https:\/\/www.wikispaces.com\/user\/view\/Streetballz","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"24567947","body":"Add me into the discussion forum thnks...
\n
\nTo calculate tension we use trigo and thus the get the least tension the angle between 2 anchors must be as small as possible so the anchor system can support a greater weight","dateCreated":"1274755978","smartDate":"May 24, 2010","userCreated":{"username":"seahshenghui","url":"https:\/\/www.wikispaces.com\/user\/view\/seahshenghui","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"24569911","body":"Please add me into the forum too. thank you. =.=
\n
\nI think it is best to try to minimize the angle between two anchor as much as possible, because the greater the V-angle, the more force will be placed on each piece of anchor. Hence, the safer way will be to put have the angle between two anchors as small as possible, so that the two anchor can bear as little weight of the load as possible and thus equalize the force between two anchor and thus making the system support a greater weight.","dateCreated":"1274760286","smartDate":"May 24, 2010","userCreated":{"username":"jeremychang","url":"https:\/\/www.wikispaces.com\/user\/view\/jeremychang","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"24570929","body":"A two point anchor system is useful, however, too large an angle will cause high tension in the ropes, thus it might not be that safe. the two point anchor system ensures that the resultant force to be 0, just that it might not be good when the angle is too big","dateCreated":"1274764099","smartDate":"May 24, 2010","userCreated":{"username":"tayjiaen","url":"https:\/\/www.wikispaces.com\/user\/view\/tayjiaen","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}}],"more":0}]},{"id":"24565701","dateCreated":"1274752641","smartDate":"May 24, 2010","userCreated":{"username":"l-ionel","url":"https:\/\/www.wikispaces.com\/user\/view\/l-ionel","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"},"monitored":false,"locked":false,"links":{"self":"https:\/\/vresolution.wikispaces.com\/share\/view\/24565701"},"dateDigested":1532092036,"startDate":null,"sharedType":"discussion","title":"Group Discussion (Lionel, Kai Yang, Kaye Wee, Wei Yang)","description":"I disagree with Max saying that a good anchor system is one that has large angle in between the two anchors. The angle in between should be small so as to have lesser tension in the anchors and hence allowing the anchors to take more weight.","replyPages":[{"page":0,"digests":[{"id":"24565963","body":"I agree with Lionel's point. However I feel that the angle between the two anchors cannot be too small either. If the angle is too small, the ropes will be very close together and this may result in the ropes tangling which may cause accidents.","dateCreated":"1274753056","smartDate":"May 24, 2010","userCreated":{"username":"kayewee","url":"https:\/\/www.wikispaces.com\/user\/view\/kayewee","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"24565969","body":"The greater the angle at the bottom of the anchor system, where the rope attaches to the anchor, the greater the force that is exerted on each anchor point.
\n
\nThe American Triangle(Death Triangle) is infamous for being a poor anchoring technique. The force on either anchor point is equal to where F is the force exerted on the lowest carabiner in the system. With an angle of 60 degrees this force is equal to the force exerted on the system. Any smaller angle will mean a greater force on the anchor points. This anchor will effectively double the forces present in the anchor system.","dateCreated":"1274753059","smartDate":"May 24, 2010","userCreated":{"username":"l-ionel","url":"https:\/\/www.wikispaces.com\/user\/view\/l-ionel","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"24566003","body":"I agree with Lionel, it doesn't make sense to want to lower the effectiveness of the anchor system by subjecting it to more tension and stress from the same downward force.","dateCreated":"1274753109","smartDate":"May 24, 2010","userCreated":{"username":"weiyang-","url":"https:\/\/www.wikispaces.com\/user\/view\/weiyang-","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"24566151","body":"Also, I think that it would be safest when the anchor system equalises forces, because that means that there will be no nett or resultant force, meaning that the climber would be able to be suspended in mid air stationary.","dateCreated":"1274753290","smartDate":"May 24, 2010","userCreated":{"username":"weiyang-","url":"https:\/\/www.wikispaces.com\/user\/view\/weiyang-","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"24567037","body":"I believe a compromise should be reached between having less tension on the rope and preventing the ropes from tangling with each other as mentioned by Lionel and Kaye Wee. Maybe 45 degrees?","dateCreated":"1274754382","smartDate":"May 24, 2010","userCreated":{"username":"TohKaiYang","url":"https:\/\/www.wikispaces.com\/user\/view\/TohKaiYang","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"24567285","body":"This is a formula i found regarding the force of each anchor:
\n
\nF(Anchor) = [F(Load)] \/ [2cos(v-angle\/2)]
\n
\nFrom the formula, it can be deduced that the smaller the v-angle (angle between two anchors), the smaller the force on the anchor.
\n
\nHence I believe a suitable v-angle would be 30 degrees as the tension on the anchor would be 52% of the weight of the load, according to the formula above.","dateCreated":"1274754826","smartDate":"May 24, 2010","userCreated":{"username":"TohKaiYang","url":"https:\/\/www.wikispaces.com\/user\/view\/TohKaiYang","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"24567303","body":"In addition, I doubt when the v-angle is 30 degrees, the rope will tangle with each other.","dateCreated":"1274754853","smartDate":"May 24, 2010","userCreated":{"username":"TohKaiYang","url":"https:\/\/www.wikispaces.com\/user\/view\/TohKaiYang","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"24567379","body":"http:\/\/www.uoregon.edu\/~opp\/climbing\/pics\/anchors\/anchor_forces.jpg<\/a>
\nThis picture from the American Mountain Guides Association manual shows how a 1000 pound load is distributed between two anchors at different angles. Therefore according to it, 40 degrees would be a good angle.","dateCreated":"1274754954","smartDate":"May 24, 2010","userCreated":{"username":"kayewee","url":"https:\/\/www.wikispaces.com\/user\/view\/kayewee","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}}],"more":0}]},{"id":"24564817","dateCreated":"1274751296","smartDate":"May 24, 2010","userCreated":{"username":"y07elliottsun","url":"https:\/\/www.wikispaces.com\/user\/view\/y07elliottsun","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"},"monitored":false,"locked":false,"links":{"self":"https:\/\/vresolution.wikispaces.com\/share\/view\/24564817"},"dateDigested":1532092037,"startDate":null,"sharedType":"discussion","title":"Group Discussion ( Elliott, Marcus, Kenneth)","description":"Vector resolution","replyPages":[{"page":0,"digests":[{"id":"24564917","body":"Discuss about vector resolution and their methods","dateCreated":"1274751486","smartDate":"May 24, 2010","userCreated":{"username":"y07elliottsun","url":"https:\/\/www.wikispaces.com\/user\/view\/y07elliottsun","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"24565061","body":"The process of determining the magnitude of a vector is known as vector resolution and there are 2 ways to determine the vector resolution and they are the parallelogram method and
\nthe trigonometric method.","dateCreated":"1274751726","smartDate":"May 24, 2010","userCreated":{"username":"Marcusee","url":"https:\/\/www.wikispaces.com\/user\/view\/Marcusee","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"24565269","body":"The smaller the angle between the two ropes, the greater the resultant force. The inverse is also true.
\n
\nBut i think when Max says that a good anchor system is one that has a large angle between them, he is also considering the vertical positions of one anchor to the other.","dateCreated":"1274752012","smartDate":"May 24, 2010","userCreated":{"username":"ongwkd","url":"https:\/\/www.wikispaces.com\/user\/view\/ongwkd","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"24565439","body":"i think it is right to say that anchor systems are safest when they equalize forces. Anchor systems are use to protect the climber from falling to the ground and therefore it must be able to exert a force equal to the weight of the person and the small force exerted by the wall, so as to keep the climber stationary in the air.","dateCreated":"1274752271","smartDate":"May 24, 2010","userCreated":{"username":"ongwkd","url":"https:\/\/www.wikispaces.com\/user\/view\/ongwkd","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"24565921","body":"An anchor system that is perpendicular to each other but not on the same horizontal level. What do you mean by that o.o?","dateCreated":"1274752970","smartDate":"May 24, 2010","userCreated":{"username":"y07elliottsun","url":"https:\/\/www.wikispaces.com\/user\/view\/y07elliottsun","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"24566703","body":"but but but, then why must it be perpendicular?","dateCreated":"1274753960","smartDate":"May 24, 2010","userCreated":{"username":"y07elliottsun","url":"https:\/\/www.wikispaces.com\/user\/view\/y07elliottsun","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"24567161","body":"btw ms tan if you're seeing this daniel is in our group too","dateCreated":"1274754595","smartDate":"May 24, 2010","userCreated":{"username":"y07elliottsun","url":"https:\/\/www.wikispaces.com\/user\/view\/y07elliottsun","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"24568095","body":"An anchor system that is perpendicular to each other but not on the same horizontal level.
\n
\nI think it means that the anchors can be on the same diagonal plane, or vertical plane, not necessarily on the horizontal plane, but nonetheless, the rope extending to the caribena should be perpendicular to each other.","dateCreated":"1274756196","smartDate":"May 24, 2010","userCreated":{"username":"ongwkd","url":"https:\/\/www.wikispaces.com\/user\/view\/ongwkd","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"24568833","body":"oh okay thanks","dateCreated":"1274757333","smartDate":"May 24, 2010","userCreated":{"username":"y07elliottsun","url":"https:\/\/www.wikispaces.com\/user\/view\/y07elliottsun","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"24570811","body":"The vector sum of the 2 ropes from the two anchor points will be equal to the max weight that the anchor system can support.
\nTherefore, the smaller the angle, the safer the climb as more weight can be supported by the anchor system","dateCreated":"1274763558","smartDate":"May 24, 2010","userCreated":{"username":"kenneth_lim_wk","url":"https:\/\/www.wikispaces.com\/user\/view\/kenneth_lim_wk","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}}],"more":0}]},{"id":"24564731","dateCreated":"1274751181","smartDate":"May 24, 2010","userCreated":{"username":"kfshihlei","url":"https:\/\/www.wikispaces.com\/user\/view\/kfshihlei","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"},"monitored":false,"locked":false,"links":{"self":"https:\/\/vresolution.wikispaces.com\/share\/view\/24564731"},"dateDigested":1532092038,"startDate":null,"sharedType":"discussion","title":"Group Discussion (Wen Bin, Kelvin, Samuel Lim, Jing Han)","description":"So this is trigo? =D
\nKelvin (4O113)","replyPages":[{"page":0,"digests":[{"id":"24565059","body":"Yeah trigo is used in the process to calculate the force. This topic is also related to Force, learnt in sec 3","dateCreated":"1274751726","smartDate":"May 24, 2010","userCreated":{"username":"3o118","url":"https:\/\/www.wikispaces.com\/user\/view\/3o118","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"24565445","body":"oh yea, I think we did this for EOY is it?
\nI remember looking through it O.o
\nMaybe that's why Ms Tan's not going through this O.o","dateCreated":"1274752286","smartDate":"May 24, 2010","userCreated":{"username":"kfshihlei","url":"https:\/\/www.wikispaces.com\/user\/view\/kfshihlei","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"24565993","body":"Its vector addition from last year. Just abit of adjustments from one-dimension to two-dimension.","dateCreated":"1274753098","smartDate":"May 24, 2010","userCreated":{"username":"3o129","url":"https:\/\/www.wikispaces.com\/user\/view\/3o129","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"24566187","body":"oh wait there is the animation we need to discuss =P
\n
\ni think both guys are wrong, should be same level, smallest possible angle (shown in the Physics Teacher Rock Climbing video)
\n
\nAny other views?","dateCreated":"1274753327","smartDate":"May 24, 2010","userCreated":{"username":"kfshihlei","url":"https:\/\/www.wikispaces.com\/user\/view\/kfshihlei","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"24567715","body":"correction:
\nsmallest possible in whereby the 2 sections of rope do not cross over each other easily to prevent fraying due to friction.
\n
\nPerhaps big angle for more comfort when u slip and it breaks your fall, small angle to support more downward force","dateCreated":"1274755578","smartDate":"May 24, 2010","userCreated":{"username":"kfshihlei","url":"https:\/\/www.wikispaces.com\/user\/view\/kfshihlei","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}}],"more":0}]},{"id":"24564495","dateCreated":"1274750780","smartDate":"May 24, 2010","userCreated":{"username":"chunfai","url":"https:\/\/www.wikispaces.com\/user\/view\/chunfai","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"},"monitored":false,"locked":false,"links":{"self":"https:\/\/vresolution.wikispaces.com\/share\/view\/24564495"},"dateDigested":1532092039,"startDate":null,"sharedType":"discussion","title":"Group Discussions (Members: ChunFai, Feng Juin, Junwei, Binhao)","description":" I disagree with Max because he says that a good 2 point anchor system is one that has a large angle in between the 2 anchors. However, i find that this is not true. The 2 anchors should be placed out as little as possible with the angle in between the 2 anchors being smaller.
\n
\n A smaller angle between the 2 anchors would give a greater resultant force. The smaller the angle between the 2 anchors, the larger the weight the anchor system can support. Hence, i think that the angle between the 2 anchors must be small.","replyPages":[{"page":0,"digests":[{"id":"24565109","body":"i agree with chun fai. Let say the load is 10N, then to have a safe anchor system, the angle should be lesser than 60 degrees for the load to be equalised and create lesser tension on the ropes so that they will not break. To big an angle, and the tension on the ropes will increase","dateCreated":"1274751794","smartDate":"May 24, 2010","userCreated":{"username":"erbinhao","url":"https:\/\/www.wikispaces.com\/user\/view\/erbinhao","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"24565117","body":"The angles should be less than 60degrees and no more than 90degrees, so that the resultant force will not be too great, and the ropes will not be too close together.
\n
\nThe ropes being too close together might result in the ropes fraying from contact, as the ropes might rub against each other when belaying.","dateCreated":"1274751807","smartDate":"May 24, 2010","userCreated":{"username":"fjer","url":"https:\/\/www.wikispaces.com\/user\/view\/fjer","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"24565575","body":"I agree that the angles should be as small as possible to allow supporting of a greater weight.
\n
\nHowever, if the ropes have a smaller angle, this would lead to more problems such as tangling and ropes from fraying which should be avoided. Thus, i think that the ropes should have an angle of 60 to 90 degrees, to sustain the most weight at the same time prevent from accidents","dateCreated":"1274752466","smartDate":"May 24, 2010","userCreated":{"username":"kjwflux","url":"https:\/\/www.wikispaces.com\/user\/view\/kjwflux","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}}],"more":0}]},{"id":"24529735","dateCreated":"1274704810","smartDate":"May 24, 2010","userCreated":{"username":"samlee3794","url":"https:\/\/www.wikispaces.com\/user\/view\/samlee3794","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"},"monitored":false,"locked":false,"links":{"self":"https:\/\/vresolution.wikispaces.com\/share\/view\/24529735"},"dateDigested":1532092039,"startDate":null,"sharedType":"discussion","title":"Group discussion (members: Liao Kai, Jeremy Chang Chee Kin, Samuel Lee)","description":"Aims of a good two point anchor system:
\n1. Spread the load equally between two anchor point
\n2. Reduce the load exerted on both anchor point
\n
\nFormula for calculation
\n
\nF(anchor) = F(load) \/ 2cos(\u03b8\/2)
\nFirst scenario:
\nLargest angle between the two anchor points
\nSince they did not state the angle, let us assume it is the largest angle possible.
\nFor cosine to be positive, the largest value is 89.99 ~ 89, hence, \u03b8 will be 179.9999, close to 180, nearly a straight line.
\n2cos(\u03b8\/2) will therefore be 0.0348 (3 s.f.), hence the force on each anchor will be more than the force of the load which is not what we aim to get.
\nSecond scenario:
\n90 degrees between the two anchor points, but both anchor points are not at the same level.
\n2cos(\u03b8\/2) will therefore be 1.41 (3 s.f), each anchor will carry about 59% of the total load, much better than in the first scenario.
\nHowever, this is not the best choice as different loads are placed on the two anchor points, the anchor point that is stressed most is prone to failure, hence, there should be ideally placed at the same horizontal level.","replyPages":[{"page":0,"digests":[{"id":"24529819","body":"on both anchor points* sorry, typo","dateCreated":"1274704895","smartDate":"May 24, 2010","userCreated":{"username":"samlee3794","url":"https:\/\/www.wikispaces.com\/user\/view\/samlee3794","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"24529893","body":"The two points of the anchor system should be spaced out as little as possible, hence naturally the angle between the two points has to be be small to give the greatest resultant force. Also, the climber should be hooked on to the exact middle portion between the two points so as to not unbalance the weight acting on each side of the anchor system.","dateCreated":"1274705030","smartDate":"May 24, 2010","userCreated":{"username":"liaokai1994","url":"https:\/\/www.wikispaces.com\/user\/view\/liaokai1994","imageUrl":"https:\/\/www.wikispaces.com\/user\/pic\/1243422620\/liaokai1994-lg.jpg"}},{"id":"24530069","body":"the best case scenarior would be that the angle is approaching 0, hence, the force on each anchor would be half of the total force exerted by the load. However, there are practical concerns like both ropes getting entangled, fraying because of abrasion, or that a freak accident may slice both rope at once because of their close proximity (if the ropes are spaced far apart, chances are that there would be still on rope intact)","dateCreated":"1274705331","smartDate":"May 24, 2010","userCreated":{"username":"samlee3794","url":"https:\/\/www.wikispaces.com\/user\/view\/samlee3794","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"24530189","body":"I agree with both Samuel and Liao Kai's points. To add on further to this discussion, in order for the two anchor points to be able to support as much downwards force as possible, the two anchor points should be as close to each other as possible and the force can be distributed proportionally between the two anchor points. Also, it is not feasible for the two anchor points to be placed as far apart from each other, as if doing so means that the mountain climbers would go through so much hassle to try and place the anchor points as "spreaded out" as possible with the greatest distance separating the two anchor points, in order to achieve the greatest strength of the two point anchor system. Again, this would be unrealistic.","dateCreated":"1274705540","smartDate":"May 24, 2010","userCreated":{"username":"jeremychangck","url":"https:\/\/www.wikispaces.com\/user\/view\/jeremychangck","imageUrl":"https:\/\/ssl.wikicdn.com\/i\/user_none_lg.jpg"}},{"id":"24530295","body":"Another reason why the two supporting sides of an anchor system are not build side by side is because of the potential loss of grip on the rock wall or whatever surface it grips onto. By spacing the sides apart, however little it may be, reduces the chances of this happening.","dateCreated":"1274705674","smartDate":"May 24, 2010","userCreated":{"username":"liaokai1994","url":"https:\/\/www.wikispaces.com\/user\/view\/liaokai1994","imageUrl":"https:\/\/www.wikispaces.com\/user\/pic\/1243422620\/liaokai1994-lg.jpg"}}],"more":0}]},{"id":"24529647","dateCreated":"1274704710","smartDate":"May 24, 2010","userCreated":{"username":"liaokai1994","url":"https:\/\/www.wikispaces.com\/user\/view\/liaokai1994","imageUrl":"https:\/\/www.wikispaces.com\/user\/pic\/1243422620\/liaokai1994-lg.jpg"},"monitored":false,"locked":false,"links":{"self":"https:\/\/vresolution.wikispaces.com\/share\/view\/24529647"},"dateDigested":1532092040,"startDate":null,"sharedType":"discussion","title":"afa","description":"fdf","replyPages":[{"page":0,"digests":[{"id":"24529699","body":"Sorry was just trying out the functions. How do I delete the post??","dateCreated":"1274704771","smartDate":"May 24, 2010","userCreated":{"username":"liaokai1994","url":"https:\/\/www.wikispaces.com\/user\/view\/liaokai1994","imageUrl":"https:\/\/www.wikispaces.com\/user\/pic\/1243422620\/liaokai1994-lg.jpg"}}],"more":0}]}],"more":false},"comments":[]},"http":{"code":200,"status":"OK"},"redirectUrl":null,"javascript":null,"notices":{"warning":[],"error":[],"info":[],"success":[]}}