单项选择题
等直圆轴,作用外力偶矩m1和m(图5-4-8),轴总扭转角为零时m1与m的关系为:()
A.m1=4m B.m1=3m C.m1=2m D.m1=1.5m
A.4m/Wp B.5m/Wp C.6m/Wp D.8m/Wp
A.35MPa B.38MPa C.42MPa D.50MPa