Question

如圖所示，長(zhǎng)12m，質(zhì)量100kg的小車(chē)靜止在光滑水平地面上。一質(zhì)量為50kg的人從小車(chē)左端，以4m/s²加速度向右勻加速跑至小車(chē)的右端（人的初速度為零）。求：

（1）小車(chē)的加速度大小；

（2）人從開(kāi)始起跑至到達(dá)小車(chē)右端所經(jīng)歷的時(shí)間；

（3）人從開(kāi)始起跑至到達(dá)小車(chē)右端對(duì)小車(chē)所做的功。

Answer 1

解：（1）對(duì)人有,                                                                

對(duì)板有,                                                                     

板與人水平方向相互作用,故大小相等

解得板 a₂=2m/s²                                                                       

（2）,                                                                                 

,                                                                             

,                                                                              

解得t=2s                                                                                       

（3）木板末速度                                                               

                                         

解析:

略