Please choose the correct answer to the question: Alicia gives her brother a push while he is seated on a swing. She finds that after a few seconds, she needs to push again to keep him going. The reason her brother slows down is because the mechanical energy is converted into

Answer1: potential energy that heats the air. Answer2: chemical energy that moves the swing. Answer3: kinetic energy which makes the swing slow down. Answer4: thermal energy that is released into the atmosphere.

Answer format: answer1/answer2/answer3/answer4
Answer: answer4