一作直线运动的物体,其位移s与时间t的关系是s=3t-t2.(1)求此物

一作直线运动的物体,其位移s与时间t的关系是s=3tt2.

(1)求此物体的初速度;

(2)求此物体在t=2时的瞬时速度;

(3)求t =0到t =2时的平均速度.

答案

解:(1)v0=

=

==3.

(2)v2=

==-1.

(3)===1.

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