在什么表面上球滚的最快回答有英文的!急,明天要交!(on what surface did a ball roll fastest?)

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在什么表面上球滚的最快回答有英文的!急,明天要交!(on what surface did a ball roll fastest?)

在什么表面上球滚的最快回答有英文的!急,明天要交!(on what surface did a ball roll fastest?)
在什么表面上球滚的最快
回答有英文的!急,明天要交!(on what surface did a ball roll fastest?)

在什么表面上球滚的最快回答有英文的!急,明天要交!(on what surface did a ball roll fastest?)
斜面

the surface without friction没有摩擦力的表面
或者 or
bevel 斜面

on a frictional inclined surface whose coefficient of kinetic friction(u) satisfies u=(2/7)×tan(a), where a denotes the inclined angle of the surface.
The underlying principle is to make the ball ...

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on a frictional inclined surface whose coefficient of kinetic friction(u) satisfies u=(2/7)×tan(a), where a denotes the inclined angle of the surface.
The underlying principle is to make the ball rotate without sliding.
A--linear acceleration along the surface
linear motion: mgsina-umgcosa=mA
rotation: 2/5mr^2 * b = umgcosa * r (r--radius of the solid sphere, b--angular acceleration)
non-sliding condition a=b*r
solve the above 3 equations and get u=(2/7)×tan(a)

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The surface without friction没有摩擦力的表面