Engineering Mechanics MCQs

Question 1

Kinetic friction is the

Accepted Answer

The friction force acting when the body is in motion

Answer

Tangent of angle between normal reaction and the resultant of normal reaction and the limiting friction

Answer

Ratio of limiting friction and normal reaction

Answer

The friction force acting when the body is just about to move

Question 2

Two non-collinear parallel equal forces acting in opposite direction

Accepted Answer

Constitute a couple

Answer

Balance each other

Answer

Constitute a moment

Answer

Constitute a moment of couple

Question 3

On a ladder resting on smooth ground and leaning against vertical wall, the force of friction will be

Accepted Answer

Upwards at its upper end

Answer

Towards the wall at its upper end

Answer

Away from the wall at its upper end

Answer

Downwards at its upper end

Question 4

On the ladder resting on the ground and leaning against a smooth vertical wall, the force of friction will be

Accepted Answer

Zero at its upper end

Answer

Downwards at its upper end

Answer

Upwards at its upper end

Answer

Perpendicular to the wall at its upper end

Question 5

Lami's theorem states that

Accepted Answer

If three forces acting at a point are in equilibrium, each force is proportional to the sine of the angle between the other two

Answer

Three forces acting at a point will be in equilibrium

Answer

Three forces acting at a point can be represented by a triangle, each side being proportional to force

Answer

If three forces acting upon a particle are represented in magnitude and direction by the sides of a triangle, taken in order, they will be in equilibrium

Question 6

Moment of inertia of a circular section about its diameter (d) is

Accepted Answer

$$\frac{{\pi {{	ext{d}}^4}}}{{64}}$$

Answer

$$\frac{{\pi {{	ext{d}}^3}}}{{16}}$$

Answer

$$\frac{{\pi {{	ext{d}}^3}}}{{32}}$$

Answer

$$\frac{{\pi {{	ext{d}}^4}}}{{32}}$$

Question 7

The range of projectile (R) on an upward inclined plane is

Accepted Answer

$$\frac{{2{{	ext{u}}^2}\sin \left( {\alpha - \beta } ight)\cos \alpha }}{{{	ext{g}}{{\cos }^2}\beta }}$$

Answer

$$\frac{{{	ext{g}}{{\cos }^2}\beta }}{{2{{	ext{u}}^2}\sin \left( {\alpha + \beta } ight)\cos \alpha }}$$

Answer

$$\frac{{2{{	ext{u}}^2}\sin \left( {\alpha + \beta } ight)\cos \alpha }}{{{	ext{g}}{{\cos }^2}\beta }}$$

Answer

$$\frac{{{	ext{g}}{{\cos }^2}\beta }}{{2{{	ext{u}}^2}\sin \left( {\alpha - \beta } ight)\cos \alpha }}$$

Question 8

If a number of forces are acting at a point, their resultant will be inclined at an angle $$	heta $$ with the horizontal, such that

Accepted Answer

$$	an 	heta = \frac{{\sum {	ext{V}} }}{{\sum {	ext{H}} }}$$

Answer

$$	an 	heta = \frac{{\sum {	ext{H}} }}{{\sum {	ext{V}} }}$$

Answer

$$	an 	heta = \sum {{	ext{V}} 	imes \sum {	ext{H}} } $$

Answer

$$	an 	heta = \sqrt {\sum {{	ext{V}} + \sum {	ext{H}} } } $$

Question 9

Two coplanar couples having equal and opposite moments

Accepted Answer

Cannot balance each other

Answer

Balance each other

Answer

Produce a couple and an unbalanced force

Answer

Are equivalent