Question

用如圖1實(shí)驗(yàn)裝置驗(yàn)證m₁、m₂組成的系統(tǒng)機(jī)械能守恒．m₂從高處由靜止開始下落，m₁上拖著的紙帶打出一系列的點(diǎn)，對(duì)紙帶上的點(diǎn)跡進(jìn)行測(cè)量，即可驗(yàn)證機(jī)械能守恒定律．圖給出的是實(shí)驗(yàn)中獲取的一條紙帶：0是打下的第一個(gè)點(diǎn)，每相鄰兩計(jì)數(shù)點(diǎn)間還有4個(gè)點(diǎn)（圖中未標(biāo)出），計(jì)數(shù)點(diǎn)間的距離如圖2所示．已知m₁=50g、m₂=150g，則（g取10m/s²，結(jié)果保留兩位有效數(shù)字）                                                                                                                

                

①下面列舉了該實(shí)驗(yàn)的幾個(gè)操作步驟：其中操作不當(dāng)步驟                               （填選項(xiàng)對(duì)應(yīng)的字母）．            

A．按照?qǐng)D示的裝置安裝器件；                                                                                  

B．將打點(diǎn)計(jì)時(shí)器接到直流電源上；                                                                           

C．先釋放m₂，再接通電源打出一條紙帶；                                                               

D．測(cè)量紙帶上某些點(diǎn)間的距離．                                                                              

E．根據(jù)測(cè)量的結(jié)果，分別計(jì)算系統(tǒng)減少的重力勢(shì)能和增加的動(dòng)能．                             

②若某同學(xué)作出v²/2﹣h圖象如圖3，寫出計(jì)算當(dāng)?shù)刂亓�加速度g的表達(dá)式              ，并計(jì)算出當(dāng)?shù)氐膶?shí)際重力加速度g=                                                                                                       m/s²．

                                                                                                                                 

Answer 1

①BC，②，9.7．