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UNIT 1 – area of study 2 Biomechanical movement principles. PROJECTILE MOTION. What does this picture mean to you?. PROJECTILE MOTION. # Projectile motion is very common in sporting situations. # Once a person or object becomes airborne it becomes a projectile. # Examples :
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UNIT 1 – area of study 2Biomechanical movement principles PROJECTILE MOTION
PROJECTILE MOTION # Projectile motion is very common in sporting situations. # Once a person or object becomes airborne it becomes a projectile. # Examples : ball sports ( tennis / volleyball ) gymnastics ( vault / floor ) athletics ( javelin / high jump )
FACTORS AFFECTING PROJECTILES • FACTORS THAT CANNOT BE CONTROLLED BY THE PERFORMER : * GRAVITY * AIR RESISTANCE • FACTORS THAT CAN BE CONTROLLED BY THE PERFORMER : * VELOCITY OF RELEASE * ANGLE OF RELEASE * HEIGHT OF RELEASE * SPIN
FACTORS AFFECTING PROJECTILES • GRAVITY • Gravity is a constant force that pulls projectiles down towards earth. • It is gravity that creates a projectile’s PARABOLIC fight path. -------- PARABOLA
FACTORS AFFECTING PROJECTILES • AIR RESISTANCE • Air resistance acts in the opposite direction to a projectile’s flight and slows its horizontal velocity. • Therefore air resistance reduces the horizontal distance a projectile will travel. -----------NO AIR RESISTANCE AIR RESISTANCE--------
FACTORS AFFECTING PROJECTILES • VELOCITY OF RELEASE • Velocity of release is the most important factor when trying to maximise the horizontal distance a projectile will travel. • The greater the force applied, the greater will be the velocity at release and the further the projectile will go.
FACTORS AFFECTING PROJECTILES • VELOCITY OF RELEASE • Velocity of release is the most important factor when trying to maximise the horizontal distance a projectile will travel. • The greater the force applied, the greater will be the velocity at release and the further the projectile will go. SLOW RELEASE--------
FACTORS AFFECTING PROJECTILES • VELOCITY OF RELEASE • Velocity of release is the most important factor when trying to maximise the horizontal distance a projectile will travel. • The greater the force applied, the greater will be the velocity at release and the further the projectile will go. SLOW RELEASE-------- FASTER RELEASE--------
FACTORS AFFECTING PROJECTILES • VELOCITY OF RELEASE • Velocity of release is the most important factor when trying to maximise the horizontal distance a projectile will travel. • The greater the force applied, the greater will be the velocity at release and the further the projectile will go. --------FASTEST RELEASE SLOW RELEASE-------- FASTER RELEASE--------
FACTORS AFFECTING PROJECTILES • ANGLE OF RELEASE • The angle of release is the angle the object is projected into the air and will depend on the sport. * volleyball block = straight up * high jump = relatively high projection * tennis forehand = relatively flat projection * lawn bowls = straight out • Where the release and landing points are at the same level the best angle for maximum horizontal distance is 45 degrees. This gives the best combination of vertical velocity to give optimal flight time and horizontal velocity to give distance.
FACTORS AFFECTING PROJECTILES • ANGLE OF RELEASE --------45 DEGREES 30 DEGREES-------- 60 DEGREES--------
FACTORS AFFECTING PROJECTILES • HEIGHT OF RELEASE • When the height of release is the same as the landing height then the best angle of release is 45 degrees. • When the point of release is higher than the landing point ( ie: shot put ) the optimal angle of release will be less than 45 degrees. • When the velocity of release and the angle of release remain constant, a projectile released from higher will travel further as it has a longer flight time.
FACTORS AFFECTING PROJECTILES • HEIGHT OF RELEASE • When the height of release is the same as the landing height then the best angle of release is 45 degrees. • When the point of release is higher than the landing point ( ie: shot put ) the optimal angle of release will be less than 45 degrees. • When the velocity of release and the angle of release remain constant, a projectile released from higher will travel further as it has a longer flight time. LOW RELEASE--------
FACTORS AFFECTING PROJECTILES • HEIGHT OF RELEASE • When the height of release is the same as the landing height then the best angle of release ( for max horizontal distance ) is 45 degrees. • When the point of release is higher than the landing point ( ie: shot put ) the optimal angle of release will be less than 45 degrees. • When the velocity of release and the angle of release remain constant, a projectile released from higher will travel further as it has a longer flight time. HIGH RELEASE------- LOW RELEASE--------
FACTORS AFFECTING PROJECTILES • SPIN • THE MAGNUS EFFECT : When a ball travelling through the air is also spinning, one half of the ball spins in opposition to the oncoming air whilst the other half of the ball spins in the same direction as the oncoming air.
FACTORS AFFECTING PROJECTILES ONCOMING AIR • SPIN • THE MAGNUS EFFECT : When a ball travelling through the air is also spinning, one half of the ball spins in opposition to the oncoming air whilst the other half of the ball spins in the same direction as the oncoming air. SPIN
FACTORS AFFECTING PROJECTILES ONCOMING AIR • SPIN • THE MAGNUS EFFECT : When a ball travelling through the air is also spinning, one half of the ball spins in opposition to the oncoming air whilst the other half of the ball spins in the same direction as the oncoming air. AIR FLOW WITH THE SPIN SPIN
FACTORS AFFECTING PROJECTILES ONCOMING AIR • SPIN • THE MAGNUS EFFECT : When a ball travelling through the air is also spinning, one half of the ball spins in opposition to the oncoming air whilst the other half of the ball spins in the same direction as the oncoming air. AIR FLOW AGAINST THE SPIN AIR FLOW WITH THE SPIN SPIN
FACTORS AFFECTING PROJECTILES ONCOMING AIR • SPIN • THE MAGNUS EFFECT : When a ball travelling through the air is also spinning, one half of the ball spins in opposition to the oncoming air whilst the other half of the ball spins in the same direction as the oncoming air. • Different air flow creates a pressure difference with the ball moving from HIGH to LOW pressure. AIR FLOW AGAINST THE SPIN AIR FLOW WITH THE SPIN SPIN
FACTORS AFFECTING PROJECTILES ONCOMING AIR • SPIN • THE MAGNUS EFFECT : When a ball travelling through the air is also spinning, one half of the ball spins in opposition to the oncoming air whilst the other half of the ball spins in the same direction as the oncoming air. • Different air flow creates a pressure difference with the ball moving from HIGH to LOW pressure. AIR FLOW AGAINST THE SPIN AIR FLOW WITH THE SPIN HIGH LOW SPIN
FACTORS AFFECTING PROJECTILES BALL CURVES • SPIN • THE MAGNUS EFFECT : When a ball travelling through the air is also spinning, one half of the ball spins in opposition to the oncoming air whilst the other half of the ball spins in the same direction as the oncoming air. • Different air flow creates a pressure difference with the ball moving from HIGH to LOW pressure. AIR FLOW AGAINST THE SPIN AIR FLOW WITH THE SPIN HIGH LOW SPIN
FACTORS AFFECTING PROJECTILES • TOPSPIN SPIN
FACTORS AFFECTING PROJECTILES • TOPSPIN A HIGH pressure on the top of the ball and a LOW pressure on the bottom of the ball causes it to “DIP” in the air. HIGH SPIN LOW
FACTORS AFFECTING PROJECTILES • TOPSPIN A HIGH pressure on the top of the ball and a LOW pressure on the bottom of the ball causes it to “DIP” in the air. HIGH SPIN BALL DIPS LOW
FACTORS AFFECTING PROJECTILES • BACKSPIN SPIN
FACTORS AFFECTING PROJECTILES • BACKSPIN A HIGH pressure on the bottom of the ball and a LOW pressure on the top of the ball causes it to “HANG” in the air. LOW SPIN HIGH
FACTORS AFFECTING PROJECTILES • BACKSPIN A HIGH pressure on the bottom of the ball and a LOW pressure on the top of the ball causes it to “HANG” in the air. LOW BALL HANGS SPIN HIGH
FACTORS AFFECTING PROJECTILES • SIDESPIN SPIN
FACTORS AFFECTING PROJECTILES • SIDESPIN A HIGH pressure on one side of the ball and a LOW pressure on the other side of the ball causes it to “CURVE” in the direction of the spin. HIGH LOW SPIN
FACTORS AFFECTING PROJECTILES BALL CURVES • SIDESPIN A HIGH pressure on one side of the ball and a LOW pressure on the other side of the ball causes it to “CURVE” in the direction of the spin. HIGH LOW SPIN
FACTORS AFFECTING PROJECTILES • EFFECT OF SPIN ON REBOUND * TOPSPIN SPIN
FACTORS AFFECTING PROJECTILES • EFFECT OF SPIN ON REBOUND * TOPSPIN The ball is spinning in the same direction as its travel so friction is reduced and the ball bounces “LOW” & “FAST”. LOW & FAST SPIN
FACTORS AFFECTING PROJECTILES • EFFECT OF SPIN ON REBOUND * BACKSPIN SPIN
FACTORS AFFECTING PROJECTILES • EFFECT OF SPIN ON REBOUND * BACKSPIN The ball is spinning in the opposite direction as its travel so friction is increased and the ball bounces “SLOW” & “HIGH”. SLOW & HIGH SPIN
FACTORS AFFECTING PROJECTILES • EFFECT OF SPIN ON REBOUND * SIDESPIN SPIN
FACTORS AFFECTING PROJECTILES • EFFECT OF SPIN ON REBOUND * SIDESPIN Friction created by the ball’s spin causes it to bounce in the direction of the spin. SPIN
REVISION QUESTIONS 1. The horizontal distance a projectile travels depends on : A/ velocity at release. B/ angle of release. C/ height of release. D/ all of the above. E/ none of the above. 2. When throwing a discus for distance, providing that all else remains constant, a taller person will: A/ throw at the same angle. B/ throw at an increased angle. C/ throw at a decreased angle. D/ throw at 45 degrees. 3. When the height of release is the same as the height of the landing, the best angle of release for maximum horizontal distance is : A/ 30 degrees. B/ 45 degrees. C/ 60 degrees. D/ 90 degrees.
REVISION QUESTIONS 4. Explain the "MAGNUS EFFECT" as it relates to a spinning ball. When a ball traveling through the air is also spinning – one half of the ball spins in opposition to the oncoming air whilst the other half of the ball spins in the same direction as the oncoming air. This creates a pressure difference on the two sides of the ball with the ball always moving or curving from high pressure to low pressure zones. 5. State the effect of the following spins on the flight of a ball. Topspin : (b) Backspin : (c) Sidespin : The ball dips down in the air The ball hangs up in the air The ball curves to the side 5. State the effect of the following spins on the bounce of a ball. Topspin : (b) Backspin : (c) Sidespin : The ball bounces low and fast The ball bounces high and slow The ball bounces to the side