B.2.2.1 Projectile motion and the effects of forces on flight path Notes

Projectile Motion in Sport

1. This motion is shaped by six key factors:
   1. Initial velocity
   2. Angle of projection
   3. Height of release
   4. Gravity
   5. Air Resistance
   6. Spin

Key Factors Affecting Projectile Motion

1. Initial velocity:
   1. Starting speed of the projectile
   2. Affects both distance and height
   3. Determines overall range
2. Angle of projection:
   1. Launch angle relative to horizontal
   2. Optimal angle depends on goal
   3. Different for each sport
3. Height of release:
   1. Starting height above landing point
   2. Affects flight time and range
   3. Critical in sports like basketball and volleyball

Optimal Angles in Sport

1. Level ground projectiles:
   1. 45° maximizes range
   2. Used in shot put
   3. Ideal for horizontal targets
2. Elevated targets:
   1. Above 45° for basketball
   2. 50-60° for volleyball serves
   3. Higher angles increase peak height

Initial velocity: the power behind the motion

1. Horizontal velocity: Determines how far the projectile travels.
2. Vertical velocity: Determines how high the projectile rises.

Angle of projection: finding the perfect launch

1. The angle of projection is the angle between the projectile's path and the ground at launch.
2. This angle affects the projectile's range, height, and trajectory shape.

Key angles to remember

1. 45°: Maximizes range when the launch and landing heights are the same.
2. Less than 45°: Optimal when launching from a height (e.g., shot put).
3. Greater than 45°: Optimal when aiming for a higher target (e.g., basketball free throw).

Height of release: gaining an advantage

1. The height of release is the vertical distance between the launch point and the landing point.
2. A higher release height generally increases the projectile's range.

Gravity

1. Constantly pulls the projectile downward, causing it to follow a curved path (parabola).
2. The vertical velocity decreases on the way up, reaches zero at the peak, then increases downward due to gravity.

Air Resistance (Drag)

1. Opposes motion, slowing the projectile down, particularly in high-speed sports (e.g., golf, cycling).
2. More noticeable in objects with large surface areas or lightweight objects (e.g., shuttlecocks in badminton).
3. Impact factors:
   1. Object's mass and size
   2. Surface area
   3. Air density
   4. Speed of motion
4. Light vs. heavy objects:
   1. Shuttlecocks fall quickly
   2. Tennis balls curve more
   3. Golf balls travel further

Spin (Magnus effect)

1. Occurs when a spinning object interacts with the air, creating a difference in pressure that alters its trajectory.
2. Topspin makes a ball dip down faster (e.g., in tennis).
3. Backspin makes a ball stay in the air longer (e.g., a golf shot).
4. Sidespin curves the ball left or right (e.g., a soccer free kick).

Phases of Projectile Motion

1. Launch Phase: Object is propelled with a given velocity and angle.
2. Ascent Phase: Vertical velocity decreases due to gravity, air resistance may slow horizontal motion.
3. Apex (Peak): Vertical velocity reaches zero before the object begins descending.
4. Descent Phase: Gravity accelerates the projectile downward, air resistance continues to slow forward motion.
5. Landing: The projectile reaches the ground or target.

Practical Applications in Sports

1. Basketball Free Throws

• Players must consider the angle of projection (usually 50°–60°) to account for the hoop's height and air resistance.

2. Golf Drives

• Golfers use backspin to generate lift, counteracting gravity and extending the ball's flight.

3. Long Jump

• Athletes optimize their take-off angle (18°–27°) to balance horizontal speed and vertical lift.

Sport-Specific Applications

1. Team Sports:
   1. Soccer free kicks (curved paths)
   2. Rugby conversion kicks
   3. Basketball jump shots
2. Track and Field:
   1. Javelin throw (optimizing distance)
   2. Long jump (balancing height/distance)
   3. Shot put (maximizing range)

Environmental Factors

1. Air conditions affecting flight:
   1. Temperature
   2. Humidity
   3. Altitude
   4. Wind speed and direction
2. Impact on performance:
   1. Ball travel distance
   2. Projectile path
   3. Required adjustments