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 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

 GRAVITY  Gravity is a constant force that pulls projectiles down towards earth.  It is gravity that creates a projectile’s PARABOLIC fight path PARABOLA

 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

 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.

 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

 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. FASTER RELEASE SLOW RELEASE

 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. FASTER RELEASE SLOW RELEASE FASTEST RELEASE

 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.

 ANGLE OF RELEASE 60 DEGREES DEGREES DEGREES

 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.

 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

 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. LOW RELEASE HIGH RELEASE

 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  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 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 ONCOMING AIR AIR FLOW WITH THE SPIN

 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 ONCOMING AIR AIR FLOW WITH THE SPIN AIR FLOW AGAINST THE SPIN

 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. SPIN ONCOMING AIR AIR FLOW WITH THE SPIN AIR FLOW AGAINST THE SPIN

 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. SPIN ONCOMING AIR AIR FLOW WITH THE SPIN AIR FLOW AGAINST THE SPIN HIGHLOW

 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. SPIN AIR FLOW WITH THE SPIN AIR FLOW AGAINST THE SPIN HIGHLOW BALL CURVES

 TOPSPIN SPIN

 TOPSPIN SPIN HIGH LOW 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.

 TOPSPIN SPIN HIGH LOW BALL DIPS 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.

 BACKSPIN SPIN

 BACKSPIN SPIN HIGH LOW 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.

 BACKSPIN SPIN HIGH LOW BALL HANGS 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.

 SIDESPIN SPIN

 SIDESPIN SPIN HIGHLOW 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.

 SIDESPIN SPIN HIGHLOW BALL CURVES 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.

 EFFECT OF SPIN ON REBOUND * TOPSPIN SPIN

 EFFECT OF SPIN ON REBOUND * TOPSPIN SPIN LOW & FAST The ball is spinning in the same direction as its travel so friction is reduced and the ball bounces “LOW” & “FAST”.

 EFFECT OF SPIN ON REBOUND * BACKSPIN SPIN

 EFFECT OF SPIN ON REBOUND * BACKSPIN SPIN SLOW & HIGH The ball is spinning in the opposite direction as its travel so friction is increased and the ball bounces “SLOW” & “HIGH”.

SPIN  EFFECT OF SPIN ON REBOUND * SIDESPIN

SPIN Friction created by the ball’s spin causes it to bounce in the direction of the spin.  EFFECT OF SPIN ON REBOUND * SIDESPIN

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.

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. (a)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. (a)Topspin : (b) Backspin : (c) Sidespin : The ball bounces low and fast The ball bounces high and slow The ball bounces to the side