Four people are playing tug-of-war. On the right side, Person #1 is pulling with a force of 60 N and Person #2 is pulling with a force of 70 N. On the left side, Person #3 is
pulling with a force of 30 N. How much force should Person #4 on the left side apply so
that the rope doesn’t move?

Because the earth is not round ,but it may seem round when viewed from ,our planet but true some points earth is not round was an oblate spheroid -a square that it squashed as globe however is not even a perfect oblate spheroid.in fact isaac newton's first proposed that earth was not perfectly round but it was an oblate spheroid instead.that mean a square that is squashed as its poles and swollen at the

The zone your looking for is the intertidal zone.