将一空盘放在电子秤上,将电子秤读数调整为零。然后在距盒底高度为 1.8 m 处,令小石子流自由下落,以 100 个/秒的速率注入盒中,每个小石子的质量均为 1×10 -2 kg ,落下的高度差均相同,且落入盒内后立即停止运动,若取 g = 10 m/s 2 ,则开始注入 10 s 时,秤的读数应为( )。
【简答题】The sea looks very beautiful when the sun is shining on it.It can be very terrible when there is a strong wind. The sea is very big.It covers three quarters of the earth.The sea is also very deep in s...
【简答题】完形填空 There was a very special teacher who made a far-reaching difference in my life. Fa11,1959,the first day of class at Bethesda Chevy Chase High School was about to begin, 'Who' . I asked a senior, ...