A sled is being pulled to the left by 5 dogs, each dog pulling with 6 Newtons of force. Find the net force.Is the net force 30N to the left?

No, the answer would not be 30, it would not be
multiplied. In this equation, each dog is independent of the others. If each dog pushes
the sled at  6 Newtons, you would merely add the forces together. (Five dogs, 6 Newtons
each is 5+6=11) In this case, it would be 11 Newtons. The link below should help explain
it a bit. Because all dogs are moving in the same direction, they complement each other.
If any of the dogs were moving in the other direction, you would have to cancel out and
subract.