试题与答案

“飞车走壁” 杂技表演比较受青少年的喜爱,这项运动由杂技演员驾驶摩托车,简化后的

题型:选择题

题目:

“飞车走壁” 杂技表演比较受青少年的喜爱,这项运动由杂技演员驾驶摩托车,简化后的模型如图所示,表演者沿表演台的侧壁做匀速圆周运动。若表演时杂技演员和摩托车的总质量不变,摩托车与侧壁间沿侧壁倾斜方向的摩擦力恰好为零,轨道平面离地面的高度为H,侧壁倾斜角度α不变,则下列说法中正确的是

A.摩托车做圆周运动的H越高,向心力越大

B.摩托车做圆周运动的H越高,线速度越大

C.摩托车做圆周运动的H越高,向心力做功越多.

D.摩托车对侧壁的压力随高度H变大而减小

答案:

答案:B

经分析可知向心力由重力及侧壁对摩托车弹力的合力提供,因摩托车和演员整体做匀速圆周运动,所受合外力等于向心力,因而B正确

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题型:单项选择题

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(74)处填()。

A.model

B.code

C. test

D.modify

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