压强=20N÷1cm²=20N÷0.0001m²=200000 pa=2×10^5 pa
压力比为 1:1
钉对墙的压强=20÷4mm²=20N÷0.000004m²=5000000 pa=5×10^6 pa
压强比为2×10^5 pa:5×10^6 pa=1:25
压强=20N÷1cm²=20N÷0.0001m²=200000 pa=2×10^5 pa
压力比为 1:1
钉对墙的压强=20÷4mm²=20N÷0.000004m²=5000000 pa=5×10^6 pa
压强比为2×10^5 pa:5×10^6 pa=1:25