图示螺钉在拉力F作用下。已知材料的剪切许用应力[τ]和拉伸许用应力[σ]之间的关系为：[τ]=0.6[σ]。试求螺钉直径d与钉头高度h的合理比值。
A:
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举一反三
- 以下那些操作可以新建一个背景？ A: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201907/40aa135f5f0a475f971257bb827504fb.png" /> B: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201907/9307bb62780f4beb9816a80655aa869f.png" /> C: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201907/4c22f5c8020040beaa0fe566345b7eb9.png" /> D: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201907/e66c4f191e944062b31d06d70642aa3f.png" />
- 以下那些操作可以新建一个角色？ A: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201907/be5248f5c01c40febe40711f7db7dbd8.png" /> B: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201907/bfcfceb7083741d8a0093bd21893a0f2.png" /> C: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201907/ca41a907d3b648ebb85161bf0477e47d.png" /> D: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201907/8a75d8860f284339b0d92f7c627b5c9b.png" />
- 以下操作，可以将数据放入列表A的是：（ ） A: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201907/be509830d9fa481e937a24d1e2d9ad46.png" /> B: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201907/56c2e754f3684727b65b6eb649aff2fa.png" /> C: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201907/a591d719880b457ea72ff0b84b29d4e9.png" /> D: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201907/deca818437954173af522e786916847f.png" />
- 圆的半径为r，计算圆的面积正确的是：（ ） A: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201907/c19fbad9b7a4479da24ef420164ea0b1.png" /> B: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201907/e7633147e3cd495fafb844f7a0098c20.png" /> C: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201907/15264e22e6824870a06d2014e4ba03f5.png" /> D: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201907/03f2b22667a84b5d83f9364a7ad27e1d.png" />
- 关于斜弯曲的主要特征有四种答案，试判断哪一种是正确的。 A: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201907/42375925fb1245cebbfabe4a5cde4d5a.png" /> B: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201907/6055f7367a0b466581761cb41cf73e10.png" /> C: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201907/a028bfcdbbcc4cb592fb6cd9d78b736a.png" /> D: <img src="http://image.zhihuishu.com/zhs/onlineexam/ueditor/201907/6abdbfbb54644603b4269b938e091af5.png" />