Question

1. name the missing force... a) frictional force b) normal force c) tension force d) weight force

Explanation:

When a student is sitting on a chair, the force of gravity ($F_g$) acts down - ward. According to Newton's third law, the chair exerts an upward force on the student. This upward force is the normal force which is perpendicular to the surface of contact (the seat of the chair). Frictional force acts parallel to the surface, tension force is in a rope - like object under stretch, and the weight force is already shown as $F_g$.

Answer:

b) normal force