(1)电火花计时器使用交变电流,工作电压220V;
(2)小车做匀加速直线运动,平均速度等于中间时刻的瞬时速度,故
v A =
1.0cm+1.2cm
2×0.02s =55cm/s =0.55m/s;
v B =
1.4cm+1.6cm
2×0.02s =75cm/s =0.75m/s;
(3)根据推论公式△x=aT 2,有 a=
△x
T 2 =
0.2×0.01m
(0.02s ) 2 =5.0m/ s 2 ;
故答案为:(1)交流,220;(2)0.55,0.75;(3)5.0.
(1)电火花计时器使用交变电流,工作电压220V;
(2)小车做匀加速直线运动,平均速度等于中间时刻的瞬时速度,故
v A =
1.0cm+1.2cm
2×0.02s =55cm/s =0.55m/s;
v B =
1.4cm+1.6cm
2×0.02s =75cm/s =0.75m/s;
(3)根据推论公式△x=aT 2,有 a=
△x
T 2 =
0.2×0.01m
(0.02s ) 2 =5.0m/ s 2 ;
故答案为:(1)交流,220;(2)0.55,0.75;(3)5.0.