Sarah does not feel a gravitational attraction to a hammer she is holding, and there a a couple of reasons why this is so. Even though it is true that a regular hammer probably weighs less than Sarah, especially if you consider Sarah's whole body, it is also true that all of the weight of the hammer is concentrated in a very small area, while Sarah's weight is spread out over a much bigger area. The hammer is pulled to the ground by the gravity of the earth at a faster rate because of this. Another reason is that Sarah's body does not have a gravitational force like the earth has, and so therefore can not "attract" the hammer in that way.