一个半径为R的圆中,的圆心角所对的弧长为() A: 60R B: C: D: R

轮胎195/60 R 14 85 的含义

研磨铰刀时机床速度以（）为宜， 如果研磨的铰刀直径过大则取机床的最低速度。 A: A40~60r/min B: B40~70r/min C: C30~60r/min D: D30~70r/min

使用手摇式兆欧表测量绝缘电阻时，正常摇测转速为60r/min（）

A signal s(t)=3cos(20pt) (V) is quantized by a uniform quantizer, the step size of the quantizer is 0.1(V), then the minimal number of quantization level is L , the number of bits per sample is at least R , and the variance of the quantization error is T ([img=22x22]1803a28ec2869ac.png[/img]). A: L=60, R=5, T=0.000833 B: L=30, R=5, T=0.000833 C: L=60, R=5, T=0.001667 D: L=60, R=6, T=0.000833

‏A signal s(t)=3cos(20pt) (V) is quantized by a uniform quantizer, the step size of the quantizer is 0.1(V), then the minimal number of quantization level is L , the number of bits per sample is at least R , and the variance of the quantization error is T ([img=22x22]1802e166a76be1c.png[/img]).‎ A: L=60, R=5, T=0.000833 B: L=30, R=5, T=0.000833 C: L=60, R=5, T=0.001667 D: L=60, R=6, T=0.000833

一轮胎规格是215/60/R/15/89/H，其中60表示轮胎的扁平率

已知两电阻R1=30Ω和R2=60Ω并联,其总电阻R=（） A: 90Ω B: 60Ω C: 20Ω

三个电阻()R()1()=20()Ω,()R()2()=40()Ω,()R()3()=60()Ω。若()R()1()与()R()2()串联后再与()R()3()并联,()求:(()1())总电阻_____Ω;()(()2())若()R()2()与()R()3()并联后再与()R()1()串联,则总电阻又是_____Ω?

在电阻R、电感线圈L、电容器C.串联A.B.电路中R＝40Ω；XL＝30Ω；XC.＝60Ω，则阻抗ZA.B.为（）。