Please refer to the attachment for a full solution.
1. What is work: When a force is applied on a body, it may or may not move depending upon the magnitude of the force and mass of the body. For example, if one tries to push a massive rock, it will not move. The person trying to push gets tired and we will concede that he did do work, albeit unsuccessfully. However, in study of mechanics, work is said to have been done by the force on the body only if the body moves. No work is done if the body does not move.
2. Magnitude of work: The magnitude of work done by the force F in causing a displacement s is defined as the product of the displacement and component of the force in the direction of the displacement.
Since displacement s and force F are vectors, by the definition of scalar (or dot) product, work W can also be expressed as W = s . F
Work done is a scalar quantity.
3. Units of Work: ...
In this write-up the concept of Work, Energy and Power has been explained. Various types of mechanical energy, principle of conservation of mechanical energy etc. have also been explained with the help of examples.