Free-body diagrams

It might help if you call these "one-body diagrams." The idea is to draw a single object, show all the forces acting ON it, and label each force.

For example, consider Bob and Jane: they are trying to slide a heavy box across the floor, but it isn't working: the box doesn't move at all.

1. Draw a diagram showing only the box. Draw an arrow for each force acting ON the box, showing roughly the direction, size and location of each force. Make a table like this, listing all the forces and indicating the x and y components of each one. What is the total force in each direction?

      force        x            y
     --------------------------------
              |          |         
              |          |         
              |          |         
              |          |         
              |          |         
              |          |         
              |          |         
     --------------------------------
      total   |          |
     --------------------------------
     

2. Write the force from the floor on the box as a vector.

3. Now draw another freebody diagram, this time for Bob. Make another table to show the components of all forces acting on him. What is the net force on Bob in each direction?

4. Write the force from the floor on Bob as a vector.