Gordon, with mass mg, is standing on a pallet of mass mp. Both are originally at rest on a frozen pond whose surface is perfectly level. Gordon begins to walk along the pallet at a constant velocity vgp to the right relative to the pallet. Here, gp represents Gordon relative to the pallet. Assume the surface is frictionless. (Use the following as necessary: mg, mp, and vgp. Note that the subscripts are lowercase. Assume the positive direction is to the right. Indicate the direction with the signs of your answers.)