百米賽跑時(shí),假如終點(diǎn)計(jì)時(shí)員在聽(tīng)見(jiàn)起跑的槍聲后才開(kāi)始計(jì)時(shí),他記錄下來(lái)的成績(jī)準(zhǔn)確嗎?為什么?計(jì)時(shí)員應(yīng)該怎么樣才能減小誤差?
答:百米賽跑時(shí)假如終點(diǎn)的計(jì)時(shí)員在聽(tīng)到起跑的槍聲后開(kāi)始計(jì)時(shí),他記錄的成績(jī)不準(zhǔn)確,
因?yàn)槁曇舻膫鞑バ枰獣r(shí)間t=
≈0.29s,所以測(cè)得值偏小,準(zhǔn)確的做法應(yīng)是看到槍冒煙時(shí)就應(yīng)該計(jì)時(shí).