题目内容
如图所示,半径R=0.4m的光滑半圆环轨道处于竖直平面内,半圆环与粗糙的水平地面相切于圆环的端点A 且μ=0.4。一质量m=0.1kg的小球,以初速度v0=8m/s在粗糙水平地面上向左作直线运动,运动4m后,冲上竖直半圆环,经过最高点B后飞出。取重力加速度g=10m/s2。求:
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(1)小球到达A点时速度大小;
(2)小球经过B点时对轨道的压力大小;
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(1)小球到达A点时速度大小;
(2)小球经过B点时对轨道的压力大小;
(1)
(2)3N
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试题分析:(1)小球从开始运动到到达A点的过程中,由动能定理
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代入数据解得
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(2)由A点到B点由机械能守恒定律得
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在B点时根据牛顿定律
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联立上述两式可解得
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