106. The total friction that can be developed is

A.Independent of the magnitude of the area of contact

B.Proportion to the magnitude of the area of contact

C.Proportional to square of area of contact

D.None of the above.

107. A man wishes to slide a heavy block over a concrete floor by a rope. At what angle (α) the rope should be inclined with the horizontal so that the man has to exert minimum force to pull it,

A.α > Φ

B.α = Φ

C.α < Φ

D.Any angle irrespective of (Φ)

108. A body of weight W is resting at a plane inclined at 30° to the horizontal. If it is attached to a string making an angle of 60° with horizontal, find the tension in the string, if the friction angle is 30°

A.Zero

B.W/2

C.W

D.2W

109. A body is resting on a plane inclined at angle of 30° to horizontal. What force would be required to slide it down, if the coefficient of friction between body and plane is 0.3

A.Zero

B.1 kg

C.5 kg

D.Would depend on weight of body

110. Least force that starts a body along a plane acts at an angle with the plane

A.Equal to the angle of friction

B.Little more than angle of friction

C.Little less than angle of friction

D.Of zero degree

111. A body weighing 100 kg falls vertically down on a cart weighing 200 kg moving at velocity V m/sec. The velocity of cart after falling of weight would be

A.V m/sec

B.More than V m/sec

C.Less than V m/sec

D.Unpredictable

112. A weight of 500 kg is held on a smooth plane, inclined at 30° to the horizontal by a force P acting 30° above the plane. The reaction of plane on the weight will be

A.500 kg

B.250 kg

C.476 kg

D.288 kg

Page **16** of **59**