1) a 75n sack is dragged along the floor with a horizontal force of 100n to the right. the frictional force is 30n. the free body diagram will you answer the questions that follow. what letter represents fg, and what is its value? 2)looking at the free body diagram and the data given in the previous problem, what letter represents ff and what is it's value? you < 3

To solve the problem we can take a reference system with the positive vertical axis pointing down and the positive horizontal axis pointing to the right.
  If Fg is the force of gravity, it pushes the object towards the earth. In the case of this diagram it would be the one pointing downwards in the vertical, that is, the A, and its value is 75 Newtons.
  If Ff is the force of friction between the bag the ground, and the bag moves to the right, then the force of friction is to the left. In the diagram would be the letter B and its value is 30 N