Step-by-step explanation:
When the Javelin is at rest on the ground, Potential Energy and Kinetic Energy are zero. immediately the Athlete picks the javelin up from the ground, there is an increase in the Kinetic Energy this increase continues until the javelin comes to a halt. Potential Energy also increases.
As the Athlete throws javelin, there is a decrease in the Potential Energy, the Kinetic Energy increases simultaneously until the javelin hits the ground.
after which Potential Energy and Kinetic Energy becomes zero.