Workbook 2 BIOMECHANICS

Projectile

Body that moves through the air eg human body, equipment.

Trajectory

The path of a projectile follows in its passage through the air. Combination of horizontal and vertical motion. When displacement of a projectile is shown graphically it looks like a symmetrical parabola.

Horizontal motion

Distance a body travels whilst in the air

Vertical motion

Height a body travels

Projectile motion factors

Velocity, angle, height

Velocity

Higher the speed (or velocity) of release, the greater the distance a projectile will carry. The speed of release is the most important factor when maximising the distance travelled.

Angle of Release

A projectile determine the shape of a projectiles trajectory.

Angles greater than 45 degrees result in

shorter distances, greater heights and longer flight times.

A release of 45 degrees will result in

the greatest distance an object will travel.

Angles less than 45 degrees result in

shorter distances, lower heights and shorter flight times.

A 45 degree angle is selected because

at this angle of release it provides equal components of horizontal and vertical force/velocity.

Height of release

The higher the release point of the projectile, the further it will go. This is due to the ball travelling further in the air before hitting the ground.

If a projectile is released from a higher position than the landing

Time taken to reach peak height in flight is less than the time for the projectile to land. Optimal angle of release is less than 45 degrees.

Projectile is released from a lower position than the landing

Time taken to reach peak height is higher than the time for the projectile to land. Optimal angle of release is greater than 45 degrees.

Gravity

Downward force that brings the projectile back to the ground at 9.8m/sec². Gravity gives the projectile a parabola.

Air resistance

A projectile must push thorugh the atmosphere or air. As it pushes thorugh it disturbs the air creating a drag force behind it. As speed increases, so does the drag or resistance of the air. Projectile will decrease in speed due to air resistance.

Surface area of projectile

The larger the surface of the projectile, the more it is affected by air resistance. Blunt shaped objects passing hrough the air experiance thorugh the air experiance a quarter of the air resistance than streamlined tapered shapes.

The nature of the surface area of projectiles

Rough textured covering vs smooth surfaces, increases the amount of air resistance experianced during its flight path. Eg smooth ball vs Golf ball

Spin

The direction of the spin detrmines how easily airmoves past the ball and therefore creates different air presure on each side of the ball dues to the principle of air pressure.

Projectiles velocity/speed

Air resistance is greater at higher velocities as oppose to slower speeds.

Projectiles mass

Air resistance has a greater effect on lighter opbjects opposed to heavier objcets.