Engineering Mechanics

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.

Question: 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

Answer: Option D

Explanation:

No answer description available for this question.

Question: Coefficient of friction depends upon
[A].

area of contact only

[B].

nature of surface only

[C].

both (a) and (b)

[D].

none of these

Answer: Option B

Explanation:

No answer description available for this question.

Question: Coefficient of friction is the ratio of the limiting friction to the normal reaction between the two bodies.
[A].

Yes

[B].

No

Answer: Option A

Explanation:

No answer description available for this question.

Question: A body of weight W is required to move up on rough inclined plane whose angle of inclination with the horizontal is α. The effort applied parallel to the plane is given by(where μ = tanφ = Coefficient of friction between the plane and the body.)
[A].

P = W tanα

[B].

P = W tan(α + φ)

[C].

P = W (sinα + μcosα)

[D].

P = W (cosα + μsinα)

Answer: Option C

Explanation:

No answer description available for this question.

Question: A body will begin to move down an inclined plane if the angle of inclination of the plane is __________ the angle of friction.
[A].

equal to

[B].

less than

[C].

greater than

Answer: Option C

Explanation:

No answer description available for this question.

Question: The angle of inclination of the plane at which the body begins to move down the plane, is called
[A].

angle of friction

[B].

angle of repose

[C].

angle of projection

[D].

none of these

Answer: Option A

Explanation:

No answer description available for this question.

Question: The angle which the normal reaction makes with the resultant reaction is called angle of friction.
[A].

Agree

[B].

Disagree

Answer: Option A

Explanation:

No answer description available for this question.