Theory of Machine
A system of masses rotating in different parallel planes is in dynamic balance if the

Resultant force and resultant couple are both equal to zero
Resultant couple is equal to zero
Resultant force is numerically equal to the resultant couple, but neither of them need necessarily be zero
Resultant force is equal to zero

ANSWER DOWNLOAD EXAMIANS APP

Theory of Machine
Two pulleys of radii r₁ and r₂ and at distance x apart are connected by means of an open belt drive. The length of the belt is

π (r₁ + r₂) + (r₁ + r₂)²/x + 2x
π (r₁ - r₂) + (r₁ + r₂)²/x + 2x
π (r₁ + r₂) + (r₁ - r₂)²/x + 2x
π (r₁ - r₂) + (r₁ - r₂)²/x + 2x

ANSWER DOWNLOAD EXAMIANS APP