(1)a=d 8+2tm/s, dx=L(8+2r)dt, x=8t+1-180 m (2) 8 0==4,a=a=12x,a=Ra=12R,a,=R2=16Rr 1=1s时,a=12ms2,an=16ms2,a=√l22+162=20ms =m=01×20=2N,F与切线方向夹角 B=acn= arcta=53.13° 1-9 d =6+ct dt cy a,=k=(b+cr) d v R R (1)在距离中心为、宽度为d内音轨的长度为2md,激光 划过这些音轨所需的时间d=2md,整张CD的放音时间 -∫=∫02m=m(-R)=2606-2216564m (2) d 3 r=5.Ucm 时, 26/s2y mrn 时, 130 =-3.31×10-3/s2rad/s 2r×53×6500 V雨对地三V雨对车+V车对地 (1)雨滴相对于地面的水平分速度 雨滴相对于列车的水平分速度1=-3km (2)下mA=下+1n6=36n60=624mh 对车|=下车对地/c60°=36/c0s60°=72kmh3 (1) 2 2m/s d d = = t v a , 8 2 m/s d d t t x v = = + , = + − x t x t t 52 8 d (8 2 ) d , 8 180m 2 x = t +t − (2) 8m/s v0 = , x0 = −180 m 1-8 3 4 d d t t = = , 2 12 d d t t = = , 2 a R 12Rt t = = , 2 6 a R 16Rt n = = t =1s 时, 2 =12m/s at , 2 =16m/s an , 12 16 20m/s 2 2 a = + = F ma = , F = ma = 0.1 20 = 2 N , F 与 切 线 方 向 夹 角 = = = 53.13 12 16 arctan arctan t n a a 1-9 b ct t s v = = + d d , c t v at = = d d , R b ct R v an 2 2 ( + ) = = at = an , c R b ct = + 2 ( ) , c Rc b t − = 1-10 (1) 在距离中心为 r 、宽度为 d r 内音轨的长度为 2rn d r ,激光 划过这些音轨所需的时间 v rn r t 2 d d = ,整张 CD 的放音时间 (5.6 2.2 ) 4166 s 69.4min 130 6500 ( ) 2 d d 2 2 2 1 2 2 2 1 − = = = = = − = R R v n v rn r t t R R (2) 2 r v = , r = 5.0cm 时, 2 26 /s 5.0 130 = = , r n v rn v r v t r r v t 3 2 2 2 d 2 2 d d d = = − = − = − r = 5.0cm 时, 3.31 10 /s rad/s 2 5 6500 130 3 2 3 2 − = − = − 1-11 雨对地 雨对车 车对地 v v v = + (1) 雨滴相对于地面的水平分速度 v1x = 0 雨滴相对于列车的水平分速度 v2x 36i km/h = − (2) v雨对地 = v车对地 tan60 = 36tan60 = 62.4km/h v雨对车 = v车对地 /cos60 = 36/cos60 = 72km/h x y 车对地 v 雨对地 v v雨对车 30