Rope team may be used in the event of a crevasse accident, e.g. to make a Swiss pulley in order to rescue a fallen climber. For larger groups of about four people or more, recovering a fallen man is most easily done using a team pull. When "walking on a rope", the fall of one person - for example, into a crevasse - must be broken by the rest of the rope team members. So there is a danger that such a fall can endanger the entire team. On steep firn or ice-covered mountainsides, where possible and appropriate, the rope must be
Block and tackle each of the parts of the rope must be "F/n." This means the input force on the rope is "F"="F/n." Thus, the block and tackle reduces the input force by the factor "n." Ideal mechanical advantage correlates directly with velocity ratio. The velocity ratio of a tackle is the ratio between the velocity of the hauling line to that of the hauled load. A line with a mechanical advantage of 4 has a velocity ratio of 4:1. In other words, to raise a load at 1 metre per second, the hauling part of the rope must be pulled at 4