100 Unlike straight-line motion of the discus or javelin, the hammer moves in a circular path before being released. The athlete applies a centripetal force to keep the hammer moving in a circle. This force is exerted through the arms and transmitted via the wire connecting the hammer to the handle. The faster the rotations, the more force is needed to maintain control. In a jump serve, the player builds energy by bending their knees (potential energy), jumps, swings their arm (kinetic energy), and transfers energy into the ball upon contact, making it travel faster. airbone: in volo to land: atterrare LAUNCHES Launching in sports is a fundamental movement that involves an object being propelled into motion. Every launch is a combination of force application, energy conversion, and controlled motion. Whether it s a throw, a kick, or a sprint start (when an athlete or object accelerates rapidly from a stationary position), launches require the application of force and are influenced by various principles of physics. Newton s second law of motion Newton s second law of motion states that the acceleration of an object depends on the force applied to it and its mass. The greater the force exerted, the greater the acceleration, provided the mass remains constant. In launching movements, athletes generate force through their muscles to accelerate an object into motion. For example, a javelin thrower sprints in the run-up, gradually transferring energy from their legs to their arm before releasing the javelin. Impulse-momentum Impulse is the product of force and the time over which it is applied. This determines how much momentum is gained. A longer application of force results in greater momentum, leading to more powerful throws. For example, a discus thrower builds up momentum by running before launching the discus forward . Energy conversion Launching involves multiple energy conversions: chemical energy (muscles) is transformed into kinetic energy (motion). In sports like volleyball or football, when a player makes contact with the ball, kinetic energy from the arm, hand, or foot is transferred to the ball. The formula that describes this passage is the kinetic energy equation: 1 KE = mv 2 2 where: KE = kinetic energy (Jouls, J) m = mass of the object (kg) v = velocity of the object after the impact (m/s); as the object gains height, kinetic energy converts into potential energy; upon descent, potential energy transforms back into kinetic energy due to gravity. Projectile motion and launch angle Projectile motion is when airbone objects follow a parabolic trajectory determined by initial velocity, launch angle, and gravity. The angle of launch affects how far and high an object travels. A basketball free throw requires an optimal launch angle (typically around 45°) to maximise accuracy. A football player adjusting their shot angle can control whether the ball travels in a long, high arc or a fast, low trajectory. Gravity and landing Once the launch phase is over, gravity plays a crucial role in bringing the object back to the ground. Air resistance slows the object down in flight, especially for high-speed throws. 184 SCIENCE AND PHYSICS