求解大学物理质点运动学问题,第二十题,谢谢!

2025-01-01 18:44:51
推荐回答(3个)
回答1:

(1)   t1=2L/V

(2)   t2=(L/(V+U)+L/(V-U))=2L/(V(1-U^2/V^2))

(3)

飞机的飞行方向需与AB连线成θ角,cosθ=u/v,它的绝对速度就是AB(BA)方向。

往返时飞机的绝对速度V绝是相等的

    V绝=√(V^2+U^2)

往返所需时间

    t3=2L/ V绝=2L/√(V^2+U^2)=2L/(V√(1-U^2/V^2))

回答2:

1 2L/v;

2 去时的速度是 u+v, 回来的速度是u-v, 所用的时间是 L/(u+v)+L/(u-v)=2Lu/(u^2-v^2);
3 此时,来回的速度都是 根号(v^2-u^2); (此时飞机对空气的速度,空气对地的速度以及飞机对地面的速度三者构成一个直角三角形,其中飞机对空气的速度是三角形的斜边)。
所以,来回的时间为 2L/根号v^2-u^2=2L/v根号(1-u^2/v^2)

回答3:

'8级风是没有飞机起飞的

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