Wu li qi shi hen jian dan = Hua xue qi shi hen jian dan = Shu xue qi shi hen jian dan = Yang tai, qi shi hen jian dan / Xiao shou qi shi hen jian dan : Yang tai, qi shi hen jian dan/ Di qiu ke xue qi shi hen jian dan = Wo de gang qin hen jian dan : Wu li qi shi hen jian dan =: Physics made simple / Hai kou shi nian jian =