## Engineering Mechanics A semicircular disc rests on a horizontal surface with its top flat surface horizontal and circular portion touching down. The coefficient of friction between semi circular disc and horizontal surface is µ. This disc is to be pulled by a horizontal force applied at one edge and it always remains horizontal. When the disc is about to start moving, its top horizontal force will

None of these
Slant down towards direction of pull
Remain horizontal
Slant up towards direction of pull

bd³/12
db³/36
bd³/36
db³/12

## Engineering Mechanics Work done is said to be zero, when

Some force acts on a body, but displacement is zero
None of these
No force acts on a body but some displacement takes place
Either (A) or (B)

## Engineering Mechanics A ladder is resting on a smooth ground and leaning against a rough vertical wall. The force of friction will act

Towards the wall at its upper end
Upward at its upper end
Downward at its upper end
Away from the wall at its upper end

## Engineering Mechanics The bodies which rebound after impact are called

Neither elastic nor inelastic bodies
Inelastic bodies
Elastic bodies
None of these

## Engineering Mechanics If a number of forces are acting at a point, their resultant is given by

(∑V)2 +(∑H)2 +2(∑V)(∑H)
√[(∑V)2 +(∑H)2 +2(∑V)(∑H)]
(∑V)2 + (∑H)2
√[(∑V)2 + (∑H)2]