Theory of Machine
In under damped vibrating system, if x₁ and x₂ are the successive values of the amplitude on the same side of the mean position, then the logarithmic decrement is equal to

x₁/x₂
log(x₁.x₂)
loge(x₁/x₂)
log(x₁/x₂)

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

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

ANSWER DOWNLOAD EXAMIANS APP