Question

用如圖1所示的實(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)，對紙帶上的點(diǎn)跡進(jìn)行測量，即可驗(yàn)證機(jī)械能守恒定律．圖2給出的是實(shí)驗(yàn)中獲取的一條紙帶：0是打下的第一個點(diǎn)，每相鄰計(jì)數(shù)點(diǎn)間的距離如圖2所示．已知m₁=50g，m₂=150g，則（g=9.8m/s²，所有結(jié)果均保留三位有效數(shù)字）                                                                                                                                                 

                           

（1）在紙帶上打下計(jì)數(shù)點(diǎn)5時的速度v₅=                                                                 m/s；                       

（2）在打點(diǎn)0﹣5過程中系統(tǒng)動能的增量△E_k=                                                                J，系統(tǒng)勢能的減少量△E_p=                                                            J，由此得出的結(jié)論是                                                ．

（3）若某同學(xué)做出v²﹣h圖象如圖3所示，則當(dāng)?shù)氐膶?shí)際重力加速度g=                     m/s²．                          

                                                                                                                                        

Answer 1

（1）2.40；（2）0.576；0.588；在誤差允許的范圍內(nèi)，m₁、m₂組成的系統(tǒng)機(jī)械能守恒；（3）9.7．