Theory of Machine
In a screw jack, the effort required to lower the load W is given by

P = W tan(α + φ)
P = W cos(α + φ)
P = W tan(α - φ)
P = W tan(φ - α)

ANSWER DOWNLOAD EXAMIANS APP

Theory of Machine
Open pairs are those which have

Elements of pairs not held together mechanically
Point or line contact between the two elements when in motion
Surface contact between the two elements when in motion
Two elements that permit relative motion

ANSWER DOWNLOAD EXAMIANS APP

Theory of Machine
Two pulleys of radii r₁ and r₂ and at distance x apart are connected by means of a cross 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