asportzone.com – MCQs, Mock Tests | IIT JEE Mechanical Engineering Engineering Mechanics Part-2

1 A single force and a couple acting in the same plane upon a rigid body

A balance each other B cannot balance each other C produce moment of a couple D are equivalent

✅ Correct Answer: 2

2 A body moves from rest with a constant acceleration of 5 m per sec. The distance covered in 5 sec is most nearly

A 38 m B 62.5 m C 6 m D 124 m

✅ Correct Answer: 2

3 The C.G. of a right circular solid cone of height h lies at the following distance from the base

A h/2 B J/3 C h/6 D h/4

✅ Correct Answer: 4

4 A particle inside a hollow sphere of radius r having coefficient of friction -rr can rest upto height of

A r/2 B r/A C r/% D 0.134 r

✅ Correct Answer: 4

5 In actual machinesmechanical advantage is unity

A mechanical advantage is greater than velocity ratio B mechanical advantage is equal to velocity ratio C mechanical advantage is less than velocity ratio D mechanical advantage is unity

✅ Correct Answer: 3

6 The necessary condition for forces to be in equilibrium is that these should beboth (a) and (b) aboveall be equal

A coplanar B meet at one point ; C both (a) and (b) above D all be equal

✅ Correct Answer: 3

7 In ideal machines

A mechanical advantage is greater than velocity ratio B mechanical advantage is equal to velocity ratio C mechanical advantage is less than velocity ratio D mechanical advantage is unity

✅ Correct Answer: 2

8 The co-efficient of friction depends upon

A nature of surfaces B area of contact C shape of the surfaces D ail of the above.

✅ Correct Answer: 1

9 The C.G. of a plane lamina will not be at its geometrical centre in the case of a

A right angled triangle B equilateral triangle C square D circle

✅ Correct Answer: 1

10 . If three forces acting in one plane upon a rigid body keep it in equilibrium then they must eitherbe all parallelat least two of them must meet

A meet in a point B be all parallel C at least two of them must meet D all the above are correct

✅ Correct Answer: 4

11 The angle which an inclined plane makes with the horizontal when a body placed on it is about to move down is known as angle of

A friction B limiting friction C repose D kinematic friction

✅ Correct Answer: 3

12 Which of the following is the locus of a point that moves in such a manner that its distance from a fixed point is equal to its distance from a fixed line multiplied by a constant greater than oneellipsecircle

A ellipse B hyperbola C parabola D circle

✅ Correct Answer: 2

13 If three forces acting in different planes can be represented by a triangle these will be in

A non-equilibrium B partial equilibrium C full equilibrium D unpredictable

✅ Correct Answer: 1

14 The M.I. of hollow circular section about a central axis perpendicular to section as compared to its M.I. about horizontal axis is

A same B double C half D four times

✅ Correct Answer: 2

15 Which of the following is not the unit of energy

A kg m B kcal C wattr D watt hours

✅ Correct Answer: 3

16 If a suspended body is struck at the centre of percussion then the pressure on die axis passing through the point of suspension will bezero

A maximum B minimum C zero D infinity

✅ Correct Answer: 3

17 In the equation of virtual work following force is neglectedreaction at a point or an axis fixed in space around which a body is con-all of the above

A reaction of any smooth surface with which the body is in contact B reaction of a rough surface of a body which rolls on it without slipping C reaction at a point or an axis fixed in space around which a body is con- D strained to turn

✅ Correct Answer: 4

18 The centre of percussion of a solid cylinder of radius r resting on a horizontal plane will be2r/3

A r/2 B 2r/3 C r/A D 3r/2

✅ Correct Answer: 4

19 Least force required to draw a body up the inclined plane is W sin (plane inclination + friction angle) applied in the direction

A along the plane B horizontally C vertically D at an angle equal to the angle of fric?tion to the inclined plane

✅ Correct Answer: 4

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

A towards the wall at its upper end B away from the wall at its upper end C upwards at its upper end D downwards at its upper end

✅ Correct Answer: 3

21 Tangent of angle of friction is equal to

A kinetic friction B limiting friction C angle of repose D coefficient of friction

✅ Correct Answer: 4

22 Coulomb friction is the friction betweentwo dry surfaces

A bodies having relative motion B two dry surfaces C two lubricated surfaces D solids and liquids

✅ Correct Answer: 1

23 Angle oT friction is the

A angle between normal reaction and the resultant of normal reaction and the limiting friction B ratio of limiting friction and normal reaction C he ratio of minimum friction force to the friction force acting when the body is just about to move D the ratio of minimum friction force to friction force acting when the body is in motion

✅ Correct Answer: 1

24 Dynamic friction as compared to static friction ishas no correlation.

A same B more C less D may be less of more depending on na-ture of surfaces and velocity

✅ Correct Answer: 3

25 A body of weight W on inclined plane of a being pulled up by a horizontal force P will be on the point of motion up the plane when P is equal to

A W B W sin (a + $) C Wtan(a + <|)) D Wan(a-)

✅ Correct Answer: 3

26 Kinetic friction is thethe friction force acting when the body is in motion

A tangent of angle between normal reac-tion and the resultant of normal reac-tion and the limiting friction B ratio of limiting friction and normal reaction C the friction force acting when the body is just about to move D the friction force acting when the body is in motion

✅ Correct Answer: 4

27 72. Which one of the following statements is not correctnone of the above.

A the tangent of the angle of friction is equal to coefficient of friction B the angle of repose is equal to angle of friction C the tangent of the angle of repose is equal to coefficient of friction D the sine of the angle of repose is equal to coefficient to friction

✅ Correct Answer: 4

28 The ratio of limiting friction and normal reaction is known as

A coefficient of friction B angle of friction C angle of repose D sliding friction

✅ Correct Answer: 1

29 Pick up wrong statement about friction force for dry surfaces. Friction force is

A proportional to normal load between the surfaces B dependent on the materials of contact surface C proportional to velocity of sliding D independent of the area of contact sur-faces

✅ Correct Answer: 3

30 The resultant of the following three couples 20 kg force 0.5 m arm $ ve sense 30 kg force 1 m arm - ve sense 40 kg force 0.25 m arm + ve sense having arm of 0.5 m will be

A 20 kg - ve sense B 20 kg + ve sense C 10 kg + ve sense D 10 kg - ve sense

✅ Correct Answer: 2

31 The effort required to lift a load W on a screw jack with helix angle a and angle of friction

A Wtan(a + <)>) B Wtan(a-<)>) C Wcos(a + ) D Wsin(a + <(>)

✅ Correct Answer: 1

32 Frictional force encountered after commencement of motion is calleddynamic friction.

A post friction B limiting friction C kinematic friction D frictional resistance

✅ Correct Answer: 4

33 Limiting force of friction is theminimum force of friction.

A tangent of angle between normal-reac-tion and the resultant of normal reac-tion and limiting friction B ratio of limiting friction and normal reaction C the friction force acting when the body is just about to move D the friction force acting when the body is in motion

✅ Correct Answer: 3

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

A downwards at its upper end B upwards at its upper end C perpendicular to the wall at its upper end D zero at its upper end

✅ Correct Answer: 4

35 The coefficient of friction depends onnature of surface

A area of contact B shape of surfaces C strength of surfaces D nature of surface

✅ Correct Answer: 4

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Mechanical Engineering Engineering Mechanics Part-2