Two strong boys hold a rope, each at one side. They firmly pull, horizontally, at the rope, one with a force F, the other with -F. A not so
strong girl is invited to push on the center of the rope in the vertical direction, with a force f.
Note: the x- and y-axis do not have the same scale.
Also note that a force of 980N is equivalent to lifting a person of 100 kg.
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Play the role of the girl and excert a force f. Secondly decide how much the center point of the rope may be moved down and
see what force the boys have to excert to make this come true.
The length of the rope is 5m. Why do you need to know its length?
What is the nett effect of the force the boys excert? Why do
they have to pull so hard?
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