Brad and Erin decide to have a tug of war contest. Erin pulls the rope with all her might and so does Brad. Sadly, Brad only pulls with half the force that Erin pulls with. Which way will the rope move?

Towards Erin

Explanation:

Assume Brad is pulling from left and Erin from right

Let the right direction is assumed to be positive

So Brad exerts force = - F

negative sign indicates in left direction (as we assumed right to be positive)

⇒Erin exerts a force = 2F

This force is in the right direction

Therefore net force on Rope = - F+2F=F

⇒Net force on rope is positive which means it moves in the right direction

⇒Towards Erin