If you are a student at school, this is not addressed to you.
Strictly, a force does not do work: whatever applies the force F does work and loses some of its available energy. The specified force always acts in the same direction so it cannot be responsible for the return of the particle from...
1. Newton's third law is widely misunderstood. His 'action' and 'reaction' were not forces but impulses. "An impressed force is an action to change the motion (momentum) of a body". Newton specifically denied that the equal and opposite gravitational forces between bodies were examples of...