Applied Mechanics and Graphic Statics
If a set of given forces are such that their free vectors build a closed polygon, then

The resultant force and resultant couple both may not be zero
The resultant force and resultant couple are always zero
The resultant force is zero but resultant couple may not be zero
The resultant force is zero but resultant couple is not zero

ANSWER DOWNLOAD EXAMIANS APP

Applied Mechanics and Graphic Statics
‘ω’ rad/sec is the angular velocity of a crank whose radius is ‘r’. If it makes θ° with inner dead centre and obliquity of the connecting rod ‘l’ is ‘ϕ’, the velocity v of the piston, is given by the equation

ω² (l sin ϕ + r cos φ tan θ)
ω² (l sin ϕ - r cos θ tan ϕ)
ω² (l cos ϕ + r sin ϕ tan θ)
ω (l sin ϕ + r cos ϕ tan θ)

ANSWER DOWNLOAD EXAMIANS APP