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101.

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

A.	towards the wall at its upper and	B.	away from the wall at its upper end
C.	downward at its upper end	D.	upward at its upper end

102.

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

A.	downward at its upper end	B.	upward at its upper end
C.	zero at its upper end	D.	perpendicular to the wall at its upper end

103.

In a screw jack, the effort required to lift the load is given by. Where W = Load lifted, ? = Helix angle, and ? = Angle of friction

A.	P = W tan (? ? ?)	B.	P = W tan (? + ?)
C.	P = W tan (? - ?)	D.	P = W tan (? + ?)

104.

In a screw jcak, the effort required to lower the load is

A.	less than	B.	equal to
C.	more than

105.

The velocity ratio in case of an inclined plane inclined at angle ? to the horizontal and weight being pulled up the inclined plane by vertical effort is

A.	sin ?	B.	cos ?
C.	tan ?	D.	cosec ?

106.

An ideal machine is one whose efficiency is

A.	between 60 to 70%	B.	between 70 to 80%
C.	between 80 to 90%	D.	100%

107.

The mechanical advantage of a lifting machine is the ratio of

A.	distance moved by effort to the distance moved by load	B.	load lifted to the effort applied
C.	output to the input	D.	all of the above

108.

The efficiency of a lifting machine is the ratio of

A.	output to the input	B.	work done by the machine to the work done on the machine
C.	mechanical advantage to the velocity ratio	D.	all of the above

109.

If the efficiency of a lifting machine is kept constant, its velocity ratio is

directly

inversely

110.

In ideal machines, mechanical advantage is

A.	equal to	B.	less than
C.	greater than