在一根没有质量不能伸长的细线下端系一个质量为ｍ的质点，固定在一个悬点下面，这就构成一个理想单摆．如图１所示，摆动时如图２所示，摆动周期为Ｔ＝２π，其适用条件是：不计空气阻力；摆角θ≤５°；摆球的线度远小于摆线的长度；摆线不可伸长．对于Ｔ＝２π如能熟练掌握 A mass with a mass of m is attached to the lower end of a thin line where no mass cannot be stretched and is fixed below a hanging point, which constitutes an ideal pendulum. As shown in Fig. 1, when swinging, as shown in Fig. 2, the swing period is T=2π. The applicable conditions are: air resistance is not included; the swing angle θ is less than or equal to 5°; the line of the swing ball is much smaller than the length of the cycloid; The line cannot be stretched. For T = 2π if you can master