Question

A worker pushes a large rock to the north while another worker helps by pushing it to the east. If they both exert equal force, in what direction does the rock move?

Answer 1

The rock moves exactly toward the Northeast, and the two workers are no help to each other.  Neither one makes the other one's job any easier.  

If the rock has to be moved Northeast and there are two workers available to do the job, then they should both push toward the Northeast.