Mechanical Engineering

Question: A lifting machine lifts a load of 1000N through a distance of 0.2 m by means of an effort of 200N through a distance of 1m. This machine is an ideal one.
[A].

Correct

[B].

Incorrect

Answer: Option A

Explanation:

No answer description available for this question.

Question: In actual machines, mechanical advantage is __________ velocity ratio.
[A].

equal to

[B].

less than

[C].

greater than

Answer: Option B

Explanation:

No answer description available for this question.

Question: In ideal machines, mechanical advantage is __________ velocity ratio.
[A].

equal to

[B].

less than

[C].

greater than

Answer: Option A

Explanation:

No answer description available for this question.

Question: If the efficiency of a lifting machine is kept constant, its velocity ratio is __________ propotional to its mechanical advantage.
[A].

directly

[B].

inversely

Answer: Option A

Explanation:

No answer description available for this question.

Question: An ideal machine is one whose efficiency is
[A].

between 60 and 70 %

[B].

between 70 and 80%

[C].

between 80 and 90%

[D].

100%

Answer: Option D

Explanation:

No answer description available for this question.

Question: The angle between two forces when the resultant is maximum and minimum respectively are
[A].

0° and 180°

[B].

180° and 0°

[C].

90° and 180°

[D].

90° and 0°

Answer: Option A

Explanation:

No answer description available for this question.

Question: Efficiency of a screw jack is given by(where α = Helix angle, and φ = Angle of friction.)
[A].

[B].

[C].

[D].

Answer: Option B

Explanation:

No answer description available for this question.

Question: In a screw jack, the effort required to lower the load is __________ the effort required to raise the same load.
[A].

less than

[B].

equal to

[C].

more than

Answer: Option A

Explanation:

No answer description available for this question.

Question: In a screw jack, the effort required to lift the load is given by(where W = Load lifted, α = Helix angle, and φ = Angle of friction.)
[A].

P = W tan (α – φ)

[B].

P = W tan (α + φ)

[C].

P = W tan (φ – α)

[D].

P = W cos (α + φ)

Answer: Option B

Explanation:

No answer description available for this question.

Question: 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

Answer: Option C

Explanation:

No answer description available for this question.