Theory of Machine
The frictional torque transmitted in a flat collar bearing, considering uniform wear, is (where r₁ and r₂ = External and internal radii of collar respectively)

(2/3) μ W [(r₁³ - r₂³)/(r₁² - r₂²)]
(2/3) μ W (r₁ + r₂)
(1/2) μ W (r₁ + r₂)
(1/2) μ W [(r₁³ - r₂³)/(r₁² - r₂²)]

ANSWER DOWNLOAD EXAMIANS APP

Theory of Machine
A rotor which is balanced statically but not dynamically is supported on two bearings L apart and at high speed of the rotor, reaction on the left bearing is R. The right side of the bearing is shifted to a new position 2L apart from the left bearing. At the same rotor speed, dynamic reaction on the left bearing in the new arrangement will

Become equal to R/4
Become equal to R/2
Remain same as before
Become equal to 2R

ANSWER DOWNLOAD EXAMIANS APP

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

T₁/T₂ = [(1 + μ tanθ)/(1 - μ tanθ)]n
T₁/T₂ = μ. θ. n
T₁/T₂ = (μ θ)n
T₁/T₂ = [(1 - μ tanθ)/(1 + μ tanθ)]n

ANSWER DOWNLOAD EXAMIANS APP