Final answer:
When a javelin is picked up by an athlete and thrown, there is a transfer and transformation of gravitational potential energy. As the javelin gains speed, the gravitational potential energy is transformed into kinetic energy. At the highest point of its trajectory, all the gravitational potential energy is converted into kinetic energy.
Step-by-step explanation:
When an athlete picks up a javelin, the javelin has gravitational potential energy due to its position relative to the ground. As the athlete throws the javelin, the gravitational potential energy is gradually converted into kinetic energy as the javelin gains speed.
At the highest point of its trajectory, all the gravitational potential energy is transformed into kinetic energy. On the way back down, the kinetic energy is converted back into gravitational potential energy until the javelin is stuck into the ground.
Throughout the flight of the javelin, mechanical energy is being transformed into heat energy. This is because not all of the mechanical energy is perfectly conserved due to air resistance and friction. Some of the energy is lost as heat, causing a decrease in the overall mechanical energy of the system.
On the way back down, the kinetic energy is converted back into gravitational potential energy until the javelin is stuck into the ground. Throughout the flight, mechanical energy is being transformed into heat energy due to air resistance and friction.