一道A-Level物理题(越快越好)
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一道A-Level物理题(越快越好)
A and B are points on the same line of greatest slope of a rough plane inclined at 30° to the horizontal.A is higher up the plane than B and the distance AB is 2.25m.A particle P,of mass m kg,is released from rest at A and reaches B 1.5s later.Find the coefficient of friction betweem P and the plane.
A and B are points on the same line of greatest slope of a rough plane inclined at 30° to the horizontal.A is higher up the plane than B and the distance AB is 2.25m.A particle P,of mass m kg,is released from rest at A and reaches B 1.5s later.Find the coefficient of friction betweem P and the plane.
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由时间和距离求加速度:1/2at²=d
由加速度求摩擦系数:mgsinθ-mgcosθμ=ma
代入:t=1.5,d=2.25,g=9.8,θ=π/6
解得:
a=2.
μ=0.342
由加速度求摩擦系数:mgsinθ-mgcosθμ=ma
代入:t=1.5,d=2.25,g=9.8,θ=π/6
解得:
a=2.
μ=0.342