...a collision with a nucleus of unknown mass, an α-particle scatters directly backward and loss 75% of its energy. What is the mass ratio of the nucleus...
...作者––貝拉密(Edward Bellamy)的《回顧》(Looking Backward ,1888)即是佳例––企圖根據其烏托邦中所認真規劃的藍圖來改造社會。就其...
...延長並回堵到上個收費站;即使所有的車都還在往前進。 這種被稱為反向模( backward modes)的光其實並不是新發現。在電漿(plasma) 的實驗裡,這些...
1.一台5000 kg的敞棚火車在沒有摩擦力的軌道上以22 m/s行進,此時開始下起傾盆大雨。幾分鐘後,車子的速度變為20 m/s,試問車子收集多重的雨水? Ans: 動量守恆定律,5000*22=(5000+ x)*20 得x=500 kg 2.一台1500 kg的車以2.0 m/s行進,你想要對車丟一團10公斤的粘土...
請見下圖: 圖片參考:http://i117.photobucket.com/albums/o61/billy_hywung/Nov07/Crazywave3.jpg 首先, 薄膜為一相對空氣較光密的介質, 因此, 在 1 → 2 的反射中, 光線有一個 π 的相位轉移 (phase change π), 而在 3 → 4 的反射中亦有發生 (因為在它之下的玻璃亦...
(1) First of all, time of flight of the package is found by considering the motion in vertical direction: ut + 0.5gt² = s with u = 0, g = 9.8 and s = 18 4.9t² = 18 t = 1.92 s Therefore, the horizontal distance between the package and the helicopter when the package hits the...