Black Friday: lifetime access is on a special offer in the app, until November 30. Black Friday: special offer on lifetime access, until November 30. Download
타력의 힘은 물체의 운동을 유지하는 데 중요하다.taryeog-ui him-eun mulche-ui undong-eul yujihaneun de jungyohada.The force of inertia is important for maintaining the motion of an object.