根据阿特伍德机原理,当跨过定滑轮细绳两端砝码的质量(M)和(M+Δm)相差Δm时,重力之差(Δmg)能使系统(M和M+Δm)从静止开始做匀加速直线运动。又根据单摆振动具有等时性,可利用它来记录出连续相等时间里的位移和时间。应用公式S=1/2at~2,即可求出加速度a的数值。当保持系统总质量(2M+Δm) According to the Atwood principle, when the mass (M) and (M+Δm) of the weight across the fixed pulley string differ by Δm, the difference in gravity (Δmg) enables the system (M and M+Δm) to move from Static start to do uniform acceleration linear motion. In addition, according to the single-oscillation vibration isochronism, it can be used to record the displacement and time in the same period of time. Apply the formula S=1/2at~2 to find the value of acceleration a. When maintaining the total system mass (2M+Δm)