钢板厚度为<img src="https://image.zhihuishu.com/zhs_yufa_150820/doctrans/docx2html/202108/3435c4d63731447d8a9d0d1bafbeb6c9.png" alt="3435c4d63731447d8a9d0d1bafbeb6c9.png">,剪切屈服极限<img src="https://image.zhihuishu.com/zhs_yufa_150820/doctrans/docx2html/202108/a8dd3903232e4592aebec5fb294d3e46.png" alt="a8dd3903232e4592aebec5fb294d3e46.png">,剪切强度极限<img src="https://image.zhihuishu.com/zhs_yufa_150820/doctrans/docx2html/202108/bf6b0972ce96414396af76b3f2ceefa0.png" alt="bf6b0972ce96414396af76b3f2ceefa0.png">.若用冲床在钢板上冲出直径为<img src="https://image.zhihuishu.com/zhs_yufa_150820/doctrans/docx2html/202108/108b4df0a4954d6c82df2334d01297af.png" alt="108b4df0a4954d6c82df2334d01297af.png">的圆孔,则冲头的冲压力应不小于().<img src="https://image.zhihuishu.com/zhs_yufa_150820/doctrans/docx2html/202108/3185d863023943b4879773cf9f2c4011.png" alt="3185d863023943b4879773cf9f2c4011.png">A<img src="https://image.zhihuishu.com/zhs_yufa_150820/doctrans/docx2html/202108/1336c0cc2f664a7a9d01f9e1d8d32af6.png" alt="1336c0cc2f664a7a9d01f9e1d8d32af6.png">B<img src="https://image.zhihuishu.com/zhs_yufa_150820/doctrans/docx2html/202108/080c6bcf2d03435bb5a404363d1319d6.png" alt="080c6bcf2d03435bb5a404363d1319d6.png">C<img src="https://image.zhihuishu.com/zhs_yufa_150820/doctrans/docx2html/202108/08e63f8d850744e5af60377673063f2d.png" alt="08e63f8d850744e5af60377673063f2d.png">D<img src="https://image.zhihuishu.com/zhs_yufa_150820/doctrans/docx2html/202108/cd733a27ca1f4b3dbd6ff541b7664f53.png" alt="cd733a27ca1f4b3dbd6ff541b7664f53.png">