Projectile Tennis Ball example essay topic

Bio-mechanical Principles of the Serve Bio-mechanics is the science that looks at the internal and external factors acting on the human body and the effects produced by these factors. Bio-mechanics studies what makes a body move and the results of that movement. The two main principles of the tennis serve are motion and force. Motion is the "continued change of position of an object in space" Force is the "push and pull" or the effect that one object has on another. Some definitions used when discussing motion are: Mass - amount of materials of which an object is made Weight - force of an attraction between an object and the earth. weight = mass x gravity Inertia - object's resistance to change in motion and proportions to the object's mass. Velocity - rate at which an object moves from one place to another Acceleration - rate at which velocity changes with respect to time.

Movement of the human body can only take place in the joints. The shoulder and elbow joints act as internal axes to arm movements. Any object that is released into the air becomes a projectile (tennis ball). As a human body, you and the object's you propel can be considered projectiles ie striking a tennis ball. The projectile tennis ball is governed by the principles of velocity, height and distance. The tennis balls path of flight is influenced by the force applied to it, establishing: it's velocity at release, the angle of release, the height of release, the impact and spin The most important of the forces applied to the projectile is the propelling force, and this determines how far the ball will travel.

Opposing this force are the forces of gravity, which acts on vertical motion, and air resistance, which acts on horizontal motion. Gravity's influence depends on the weight of the object. The heavier the object, the greater the acceleration towards the ground. Air resistance causes a projectile to fall to the ground before it has completed it's path.

The lighter an object and the larger the surface area, the more it is affected by air resistance e.g. a shuttlecock in badminton is affected more than a tennis ball. Air resistance also decreases speed e.g. a golf ball drive is more effected than a golf ball lifted onto the green. When throwing the tennis ball up 90 degrees from the ground, as in the serve the speed decreases gradually to zero at the maximum height of the throw. Following that gravity causes the ball to return to ground. The vertical velocity determines vertical height and timing of the flight at the time of release of the ball. The greater the speed of releases of the ball the greater the range of the ball.

This has more influence than the angle of release. The velocity of a projectile, such as the ball or racquet depends on the speed of the last part of the body, at the time of contact or release. When maximum force is required e.g. the serve, as many body parts as possible should be used. In humans the body parts that are the strongest, heaviest and with the greatest inertia are moved first.

You need to use different muscles at a time when they are capable of sufficient speed to apply full force. If a force is to be effective, the limb or body parts must be accelerated according to the resistance being moved. The longer the arm of a lever e.g. extending arm and shoulders, the greater is the speed at the end of it. If a body part is extended by a tennis racquet, the racquet strikes the ball with more speed than your hand would.

When serving in tennis you straighten your arm to increase the linear velocity at impact. A larger and heavier racquet can increase the linear velocity but is much harder to use. If you are a strong and experienced player you can use the heavier racquets advantage, because you would have the force to accelerate its greater mass a well as having the technique to provide the increased amount of time in preparation for each stroke. There is only a single release point that corresponds to an accurate performance.

So to increase the accuracy of direction the more experienced player will often flatten the arc of the direction of ball. The range of the projectile is deceased by spinning the ball e.g. during passing shots in tennis it is increased with backspin in defensive strokes. Force can be measured in magnitude, direction, and the point where force is applied in the line of action. Force can cause an object at rest to move, cause a moving object to slow down, stop, increase speed and change direction.

Newton's first law states that " an object at rest tends to stay at rest unless acted upon by some external force". An object in motion will remain in motion and travel in a straight line with uniform velocity unless acted upon by some external force. The forces that slow down objects are ground friction, air friction and gravity. Forces that speed up objects can be implements of hitting e.g. tennis rackets and body parts that apply force.

When a force is applied to an object that is moving, the object moves in the direction that the force acts. e.g. racket against ball in direction of opposite player. Momentum is the amount of motion possessed by a moving object. This is important when there is a collision with another object (racquet against ball). The greater the momentum, the greater the effect on other objects. This is important in the tennis serve. The speed in which a tennis ball is hit is dependent on the momentum of the racquet.

When playing the serve in tennis, you can adjust how hard you hit the ball by changing the velocity of the swing or by using a lighter or heavier racquet. Final Performance of the Skill of the Serve When there is a bio-mechanical accuracy aligned with proper balance and timing to achieve an accurate recognition or a return then the player achieves a synergistic fulfilment and the ball is hit well. Bio-mechanics is the term used to determine the appropriate release of energy through the physique so there can be a full usage of power, quickness in perfectly timed sequence. In response to questions of bio-mechanical applications in tennis there is a dynamic and continuous activity between players except upon the serve wherein the player is a constant movement from disequilibrium to equilibrium or balance.

Getting in this center of relaxed readiness or balance and in place to hit or swing from either side makes tennis an extremely complex game to develop. The additional variable of the racquet and grips plays an integral part in the manner in which the body will address the ball. There must be a balance in producing speed but maintaining accuracy. There must be a careful gauge of the factors that may influence the tennis ball flight in the air. The accuracy of the serve depends on several bio-mechanical factors 1. The force applied overcoming inertia to the correct degree 2.

The force applied creating the required momentum 3. The force applied acting in the required direction 4. The force applied being correctly timed 5. Complimentary movements to ensure accuracy in application of the force.