  ## Applied Mechanics MCQ Practice Questions (Civil Engineering) Set 9

##### A stone is whirled in a vertical circle, the tension in the string, is maximum:

Options are :

• At all the positions
• When the stone is at the highest position
• When the string is horizontal
• When the stone is at the lowest position

Answer :When the stone is at the lowest position

##### Angular acceleration of a particle may be expressed as:

Options are :

• Revolutions/sec
• Degrees/sec^(2)
• All the above

##### The unit of force in C.G.S. system of units, is called:

Options are :

• Dyne
• Newton
• Kg
• All the above

##### If two forces each equal to T in magnitude act at right angles, their effect may be neutralised by a third force acting along their bisector in opposite direction whose magnitude will be:

Options are :

• None of these
• 3 T
• 1/2 T
• 2 T
• ?2 T

##### On a ladder resisting on a smooth ground and leaning against a rough vertical wall, the force of friction acts:

Options are :

• Away from the wall at its upper end
• Upwards at its upper end
• Towards the wall at its upper end
• None of these
• Downwards at its upper end

Answer :Upwards at its upper end

##### Varigon's theorem of moments states:

Options are :

• Algebraic sum of the moments of two forces about any point, is equal to the moment of their resultant about that point
• Algebraic sum of the moments of the forces about any point in their plane, is equal to the moment of their resulant about that point
• Arithmetical sum of the moments of the forces about any point in their plane, is equal to the moment of their resultant about that point
• Arithmetical sum of the moments of two forces about any point, is equal to the moments of their resultant about that point

Answer :Algebraic sum of the moments of the forces about any point in their plane, is equal to the moment of their resulant about that point

##### ? rad/sec is the angular velocity of a crank whose radius is r. If it makes ?� with inner dead centre and obliquity of the connecting rod l is ?, the velocity v of the piston, is given by the equation:

Options are :

• ?^(2)(l sin ? - r cos ? tan ?)
• ?(l sin ? + r cos ? tan ?)
• ?^(2)(l sin ? + r cos ? tan ?)
• ?^(2)(l cos ? + r sin ? tan ?)

Answer :?(l sin ? + r cos ? tan ?)

##### For a particle moving with a simple harrmonic motion, the frequency is:

Options are :

• None of these
• Directly proportional to its angular velocity
• Inversely proportional to its angular velocity
• Inversely proportional to periodic time
• Directly proportional to periodic time

Answer :Inversely proportional to periodic time

##### A satellite goes on moving along its orbit round the earth due to:

Options are :

• Centripetal force
• Gravitational force
• Centrifugal force
• None of these

Options are :

• C
• B
• D
• A

##### To double the period of oscillation of a simple pendulum:

Options are :

• Its length should be doubled
• The mass of its bob should be quadrupled
• Its length should be quadrupled
• The mass of its bob should be doubled

Options are :

• 3
• 2
• 4
• 5

##### A sphere is resting on two planes BA and BC which are inclined at 45� and 60� respectively with the horizontal. The reaction on the plane BA will be:

Options are :

• Less than that on BC
• None of these
• Zero
• More than that of BC
• Equal to that on BC

Answer :More than that of BC

Options are :

• 75�
• 30�
• 60�
• 45�

Options are :

• B
• D
• C
• A

##### In simple harmonic motion, acceleration of a particle is proportional to:

Options are :

• Displacement
• Direction
• None of these
• Velocity
• Rate of change of velocity

Options are :

• 5?10 m/sec
• 10?5 m/sec
• 5?3 m/sec
• 3?5 m/sec