Answer
a. positive
b. less than the weight
Work Step by Step
a.
As the pencil falls through an arc in the first quadrant, the pencil presses the table with force pointing to the third quadrant. The reaction contact force presses back at the pencil pointing in the opposite direction, to the first quadrant. Both the x and y-components of the contact force are positive.
b.
Observing forces in the y direction, the center of mass is accelerating down, so the net force is downward, meaning that the negative downward force (weight) is greater than the positive upward force (the y-component of the contact force).
