计数点间的时间间隔t=0.02s×5=0.1s;
(1)b点的瞬时速度vb=[ac/2t]=
s1+s2
2t=[0.0706m+0.0768m/2×0.1s]=0.74m/s;
(2)纸带的加速度a=
s4−s1
3t2=
0.0892m−0.0706m
3×(0.1s)2=0.62m/s2;
(3)由牛顿第二定律得:mgsin37°-μmgcos37°=ma,解得μ=0.67;
故答案为:(1)0.74;(2)0.62;(3)0.67.
计数点间的时间间隔t=0.02s×5=0.1s;
(1)b点的瞬时速度vb=[ac/2t]=
s1+s2
2t=[0.0706m+0.0768m/2×0.1s]=0.74m/s;
(2)纸带的加速度a=
s4−s1
3t2=
0.0892m−0.0706m
3×(0.1s)2=0.62m/s2;
(3)由牛顿第二定律得:mgsin37°-μmgcos37°=ma,解得μ=0.67;
故答案为:(1)0.74;(2)0.62;(3)0.67.