Final answer:
Kinetic energy is gained during a skater's maneuver, which is the result of internal work done by the skater, such as pulling in their arms, converting food energy into motion. For example, pushing a skater results in an increase of kinetic energy, as does a skater throwing an object while on ice.
Step-by-step explanation:
The question is about how much kinetic energy is gained or created during specific maneuvers performed by skaters, and where this energy comes from. In figure skating and related performances, kinetic energy can be changed or created through various actions that athletes perform. According to the provided discussion, when a skater pulls in her arms, they are doing internal work, which converts some of the food energy they have consumed into kinetic energy. Therefore, the increase in kinetic energy is due to the work done by the skater as they change their moment of inertia.
As an example, if a 50 kg ice skater is pushed from rest with a force that results in 75 W of power for 3 seconds, it gain 225 J of kinetic energy. This energy transforms into the skater's motion, resulting in a speed of 3 m/s. Similarly, during an ice skating performance, if an 80.0-kg clown who is initially motionless throws a fake barbell away and recoils with a velocity, both the clown and the barbell gain kinetic energy. The kinetic energy is the difference between the final and initial kinetic energies of the system, and it comes from the work done during the throw.