Define work and its unit. Describe the conditions for maximum and minimum work.

Work in physics is defined as the product of the force applied to an object and the distance over which the force is applied, in the direction of the force. Mathematically, it can be expressed as:

W=F⋅d⋅cos⁡(θ)

Where:

• W is work,
• $F$ is the force applied,
• $d$ is the displacement,
• θ is the angle between the force and displacement vector.

The unit of work in the International System (SI) is the joule (J), which is defined as the work done when a force of one newton is applied to move an object by one meter in the direction of the force.

Conditions for Maximum and Minimum Work:

• Maximum work occurs when the force is applied in the same direction as the displacement. This corresponds to θ=0∘, where cos⁡(0∘)=1\, thus W=F⋅d.
• Minimum work occurs when the force is applied perpendicular to the direction of displacement, i.e., when θ=90∘. In this case, cos⁡(90∘)=0, so W=0. There is no work done in this case, even if a force is applied.