Understanding Free Body Diagrams:

• A free body diagram is a graphical illustration used to visualise the forces acting on an object.
• The object, often referred to as the 'free body', is usually represented by a simple shape like a square or a circle.
• Arrows are used to illustrate the forces. The direction of the arrow indicates the direction of the force and its length represents the magnitude of the force.
• Typically, the weight of the body (caused by gravity) is represented by a downward arrow.
• Forces in the same direction add together, while opposing forces subtract from each other.

Analysing Different Forces in Free Body Diagrams:

• The gravitational force, also known as weight, is generally represented by an arrow pointing downwards.
• The normal force is the support force exerted by a surface that an object rests on. This is usually represented by an upward arrow.
• Tension forces are exerted by any stretched flexible connector, like a rope or string. It is always directed away from the object.
• Friction forces resist motion and point in the opposite direction to the motion of the object.
• Applied forces are any forces being applied to an object, like a person pushing a box. The direction will depend on where and how the force is applied.

Working with Free Body Diagrams:

• There's no set way to draw a free body diagram; the layout depends on the specific problem to be solved.
• Make sure to include all forces acting on the object, even if they're not mentioned in the problem. It's essential to consider gravity (weight), and normal forces if the object is on a surface.
• Forces acting in opposite directions must be compared or combined appropriately. For instance, if the forces aren't balanced, expect the object to move.
• Always remember to clearly label your arrows so you and others understand what each force represents.
• Use free body diagrams to help solve physics problems involving forces, such as finding net force, acceleration, or mass.

Normal Force and Friction Relevance:

• Understanding normal force is essential for explaining why all objects at rest do not just fall through the ground, despite the earth's gravity.
• Friction is a necessary force. Without friction, moving objects would not stop on their own, and we wouldn't be able to walk without slipping.
• Changes in normal force, surface types or materials affect friction forces and can be investigated with the use of free body diagrams.

Revising the concept of free body diagrams and forces will bolster your comprehension of physics topics like dynamics, mechanics, and laws of motion.