1 - Biomechanics relates to sport science illustrating the laws of mechanic and physics applied to the structure and function of a living human system or object. It involves both external and internal forces at work and therefor the concluded effects produced by these two powers. It is necessary to have a clear understanding of the applications of physics and principles in regards to sporting activities. I have chosen the sport of sailing as an example of physics and biomechanics illustrated in relations to different forces.
2 - Above is a diagram of a commonly used sailboat. Each component of the sailboat works in maintaining a balance to create motion. But, what makes a sail boat produce motion? Of course the first that comes to mind is wind force and velocity.
3 - Lift - The shape of the sail is of upmost importance to capturing the wind to create a lift and drag force, a close second is the angle of which the sail is pointed to relating to the direction of wind travel. (Diagram of wing sail shape) faster flowing air exerts less pressure than the slower air travelling beneath the wing. This pressure difference creates an upwards force known as lift allowing a sailboat to move forward. Due to the characteristic shape of the sail, since the wind travels further over the top of the sale it must travel faster so that both streams of air meet simultaneously at the trailing end. The relationship between the sail and wind is known as the angle of attack, aerodynamic forces must develop to create movement otherwise the wind won’t create pressure. Each point of the sail has different pressures working on it. The strongest force is located at the chord end, where the curve created on the sail is at its deepest, where air flows it’s fastest and pressure drops most. (Lift force example using paper)
4 - Inertia - The forces I have just mentioned closely relate the newton’s first and third law of motion. Newton’s first law regarding inertia and illustrating that the greater the inertia, the greater the force required to move it (E.g. the bigger the sail boat the more forcer required to move it). Due to the resistive forces such as water and air, more force is necessary to overcome inertia to move the boat. Water and air also assist in changing the direction and motion of the boat through water friction and air resistance, but these forces also create decrees in speed and large sums of force are repeatedly needed to accelerate once changing the boats direction.
5 - Action/Reaction - Newton’s third law states that every action has an opposite or equal reaction, thus the wind power creating pressure against the sails, allowing the sailboat to produce motion. Wind exerts both drag force and lift force on the sail therefor the total force created by the wind is the result made from both lift and drag. The direction of motion is dependent on these two forces. When the lift force is predominantly weak compared to drag force, the total wind force is close to the winds direction. When the lift force is relatively larger compared to the force of drag, the force created is almost perpendicular to the direction of wind travel. When the sail cuts directly into the wind the sail fails to inflate and create lift and only drag is left to compensate to the movement of the boat. (Picture of wind direction relevant to sail)
But there are factors that cause resistance against producing a smooth motion of a sailboat. We’ve discussed extensively the physics of generating power from a sailboat, but we must consider the forces that oppose the motion of the boat.

6 - Water resistance - The first resistive force faced is the