將某種硫化天然橡膠在300K進(jìn)行拉伸,當(dāng)伸長(zhǎng)一倍時(shí)的拉力為7.25×105N·m-2,拉伸過(guò)程中試樣的泊松比為0.5,根據(jù)橡膠彈性理論計(jì)算: