1:46:15 將軍,您讀中學沒有念物理課嗎? 您講的在1:46:57講的七八馬赫不對,中學生都能更正您的錯誤,以後請勿犯這樣的低級錯誤! 第一宇宙速度物理課講 v_1=\sqrt{\frac{GM}{R}}, 其中, M & = 5.972 \times 10^{24} \, \text{kg} \quad \text{(mass of Earth)}, \\ R & = 6.371 \times 10^6 \, \text{m} \quad \text{(radius of Earth)}. The first cosmic speed, also known as the orbital velocity or minimum velocity required to achieve orbit around Earth, is approximately 7.91 km/s or about Mach 23.0598. This speed corresponds to the velocity needed to maintain a stable low Earth orbit without falling back due to Earth's gravitational pull.