i am back again !!yesterday went to watch transformer,it was nicer than the terminator...Thursday got no motivation to study...so went to watch movie but really regret it..how?wake up on Friday morning with all the new motivation from my guilt i wanted to study le but again didn't due to my dad ;he gave me a job by constructing a time line for him...anyway its also beneficail ,as i had got a chance to play table tennis with my dad!! so wanting to had someone in school to play with me...please learn table tennis all my friend!!!my stress is relieved...so prepared for the last workout to o levels!!!!GAMBATTE..RESILLENCE...hehe...had a doubt right now ...do longitidunal waves has amplitude?yes or no...(as a wave passess throught a ertain medium,the particles vibrate throught a distance of 5cm,parallel to the direction of a longitidunal waves ,so whats the amplitude?a amplitude definition is the position that the particle travelled from its neutral position...thus i think that this question should be improper??)