Question

站臺(tái)上有一觀察者，在火車開(kāi)動(dòng)時(shí)站在第1節(jié)車廂前端的附近，第1節(jié)車廂在5 s內(nèi)駛過(guò)此人．設(shè)火車做勻加速運(yùn)動(dòng)，求第10節(jié)車廂駛過(guò)此人需多長(zhǎng)時(shí)間?

Answer 1

0.81 s

解析：設(shè)每節(jié)車廂長(zhǎng)為x₀，根據(jù)x=v₀t+at²有：x₀=at₁₀²                        ①

10x₀=at₁₀²                                                                                         ②

9x₀=at₉²                                                                                             ③

Δt=t₁₀-t₉                                                                                                 ④

聯(lián)立①②③④式解得：Δt=（）t₁=0.81 s．