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【考题再现】25(.18分)如图,一轻弹簧原长为2R,其一端固定在倾角为37°的固定直轨道AC的底端A处,另一端位于直轨道上B处,弹簧处于自然状态,直轨道与一半径为5/6R的光滑圆弧轨道相切于C点,AC=7R,A、B、C、D均在同一竖直面内.质量为m的小物块P自C点由静止开始下滑,最低到达E点(未画出),随后P沿轨道被弹回,最高点到达F点,AF=4R,已知P与直轨道间的动摩擦因数μ=1/4,重力加速度大小为g.
Reproduction】 【25 (.18 points) As shown, a light spring original length 2R, one end fixed at a fixed angle of 37 ° straight AC at the bottom of the A, the other end is located in the straight track B, the spring In a natural state, the straight orbit is tangent to a smooth circular orbit at a radius of 5 / 6R at point C, AC = 7R, and A, B, C and D are all in the same vertical plane. Since the point C begins to decline from rest, the minimum reaches point E (not shown), then P along the track is bounced back to the highest point F, AF = 4R, known P and straight track dynamic friction coefficient μ = 1 / 4, the acceleration of gravity is g.