Question

一物體從樓上自由落下,經(jīng)過高為2 m的窗戶所用時(shí)間為0.2 s.物體是從距離窗頂多高處自由落下的?

Answer 1

4.05 m

解析：設(shè)物體落到窗頂?shù)臅r(shí)間為t,距窗頂高h(yuǎn),窗戶高h(yuǎn)₀=2 m,經(jīng)過時(shí)間t′,則:經(jīng)過窗戶中間時(shí)刻的速度:m/s=10 m/s,=g(t+)t=0.9 s,所以h=gt²=4.05 m.