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A steel ball starts rolling from rest down a steel plate inclined at 45° to the horizontal, as shown below.The plate is covered by a thin oil film of viscosity

n. = 50 [cP] and pressure viscosity coefficient a = 2.2x10° [m²/N]. The diameter of the ball is d = 3x10² [m], Young's modulus is E = 2.1x10" [Pa], Poisson's ratio is v = 0.3 and density is p = 7,800 [kg/m³]. What is the minimum thickness of the elastohydrodynamic film after the ball has rolled 1 [cm] and 1 [m]? Assume no sliding. (Ans. h, = 0.059 and 0.281 [µm])

Fig: 1

Fig: 2