Question

if student a pushes by straightening her arms while student b keeps her arms in the original position, what would describe the motion of the students?
student a does not move, and student b moves backward.
student b does not move, and student a moves backward.
both students move in opposite directions.
both students move towards each other.

Explanation:

According to Newton's third - law of motion, for every action, there is an equal and opposite reaction. When Student A pushes by straightening her arms, she exerts a force on Student B. In return, Student B exerts an equal and opposite force on Student A. Since they are on roller - skates (assumed to have low friction), both students will move in opposite directions.

Answer:

Both students move in opposite directions.