A sled sits on the snow. Three people are pulling on it with ropes. The first rope points 45◦ north of east, and a person pulls it with a force of 200 N. Another rope points southward, and someone pulls it with a force of 300 N. The third rope points 30◦ north of west, and the last person pulls it with a force of 100 N. You would like to stop the sled from moving. In which direction, and with what force, should you pull the fourth rope?