Question

質(zhì)點(diǎn)做直線運(yùn)動(dòng)的位移x與時(shí)間t的關(guān)系為x＝5t＋t²(各物理量均采用國際單位制單位)，則該質(zhì)點(diǎn)                                                                                     (　　)．

A．第1 s內(nèi)的位移是5 m

B．前2 s內(nèi)的平均速度是6 m/s

C．任意相鄰的1 s內(nèi)位移差都是1 m

D．任意1 s內(nèi)的速度增量都是2 m/s

Answer 1

解析　物體做勻變速直線運(yùn)動(dòng)，由勻變速直線運(yùn)動(dòng)規(guī)律：

＝v＝知：v＝                                                                                                  ①

v＝                                                                                                                     ②

由勻變速直線運(yùn)動(dòng)速度公式v＝v₀＋at知

v＝v＋a·                                                                                                    ③

①     ③式聯(lián)立解得a＝.

答案　D