Flywheel launchers, such as tennis ball shooters, utilize rotational kinetic energy to accelerate projectiles, with final velocity influenced by factors like inertia, elasticity, and friction. The discussion highlights that while torque is often seen as a driving force, it is the tangential velocity of the flywheel that primarily determines projectile speed, especially when inertia is significant. Compression of the projectile plays a role in energy transfer but does not necessarily increase final velocity beyond a certain point, as excessive compression does not enhance the circumferential speed of the wheel. Friction is crucial for locking the projectile in place during acceleration, but its effectiveness is influenced by the normal force from compression. Understanding these dynamics is essential for optimizing the efficiency of flywheel-based launching systems.