Machine Design
In an oil lubricated journal bearing, the coefficient of friction between the journal and the bearing

Is minimum at zero speed and increases monotonically with increase in speed
Remains constant at all speeds
Becomes minimum at an optimum speed and then increases with further increase in speed
Is maximum at zero speed and decreases monotonically with increase in speed

ANSWER DOWNLOAD EXAMIANS APP

Machine Design
In a band and block brake, the ratio of tensions on the tight and slack sides of band is given by (where μ = Coefficient of friction between the blocks and the drum, θ = Semi-angle of each block subtending at the centre of drum, and n = Number of blocks)

T₁/T₂ = [(1 + μ tanθ)/ (1 - μ tanθ)]n
T₁/T₂ = [(1 - μ tanθ)/ (1 + μ tanθ)]n
T₁/T₂ = (μθ)n
T₁/T₂ = μθ × n

ANSWER DOWNLOAD EXAMIANS APP