在剛剛結束的校運動會上，一年九班獲男子4×100m接力第一名。設該隊*乙兩同學在直跑道上進行交接棒，他們在奔跑...

問題詳情：

在剛剛結束的校運動會上，一年九班獲男子4×100m接力第一名。設該隊*乙兩同學在直跑道上進行交接棒，他們在奔跑時有相同的最大速度，最大速度為vm=8m/s，乙從靜止開始全力奔跑需跑出s0=16m才能達到最大速度，這一過程可看做是勻加速直線運動，現在*持棒以最大速度向乙奔來，乙在接力區伺機全力奔出．

（1）求乙加速過程的加速度a的大小

（2）若要求乙接棒時奔跑的速度達到v=6m/s，求乙在接力區須奔出的距離s

（3）如果乙是傻傻站着接棒，接到棒後才從靜止開始全力奔跑，求這樣會比乙恰好達到最大速度時接棒浪費的時間Δt

【回答】

(1)乙從靜止加速到最大速度vm2=2as0························································· （2分）

得a= 2m/s2·························································································· （1分）

(2)乙從靜止加速到6m/s

v2=2as·································································································· （2分）

得s=9 m······························································································· （1分）

(3若乙以最大速度跑出16m的時間為

t1＝2 s·································································································· （2分）

若乙以勻加速跑出16m

x＝at22得t2=4s················································································· （2分）

Δt= t2- t1＝2 s······················································································· （2分）

知識點：勻變速直線運動的研究單元測試

題型：計算題