Applied Mechanics 5

Objective Questions and Answers of Civil Engineering: Applied Mechanics 5

Subject: Applied Mechanics 5

Part 5: Objective questions and answers of Applied Mechanics

Q1. The unit of rotational inertia of a body in c.g.s system is

a) Cm^4

b) Kg-cm^2

c) Gm-cm^2

d) Gm-cm^3

Q2. A ladder of weight ‘w’ rests against a smooth vertical wall, and rests on rough horizontal ground, the coefficient of friction between the ladder and the ground being 1/4. The maximum angle of inclination of the ladder to the vertical, if a man of weight ‘w’ is to walk to the top of it safely, is tan’1 x, where x is

a) 1/4

b) 1/3

c) 3

d) 4

Q3. A light rope is loaded with many equal weights at equal horizontal intervals. The points of suspension on the rope lie on a

a) Parabola

b) Catenary

c) Cycloid

d) Ellipse

Q4. A heavy ladder resting on floor and against a vertical wall may not be in equilibrium if

a) Floor is smooth and wall is rough

b) Floor is rough and wall is rough

c) Both floor and wall are rough

d) Both floor and wall are smooth

Q5. The shape of a suspended cable for a uniformly distributed load over it is

a) Circular

b) Parabolic

c) Catenary

d) Cubic parabola

Q6. Impulse can be obtained from a

a) Force-displacement diagram

b) Force-time diagram

c) Velocity-time diagram

d) Velocity-displacement diagram

Q7. A cable loaded with 10 kn/m of span is stretched between supports in the same horizontal line 100 m apart. If the central dip is 10 m, then the maximum and minimum pull in the cable respectively are

a) 1346.3 kn and 1500 kn

b) 1436.2 kn and 1250 kn

c) 1346.3 kn and 1250 kn

d) 1436.2 kn and 1500 kn

Q8. A ball moving on a smooth horizontal table hits a rough vertical wall, the coefficient of restitution between ball and wall being 1/3. The ball rebounds at the same angle. The fraction of its kinetic energy lost is

a) 1/3

b) 2/3

c) 1/9

d) 8/9

Q9. A ball is dropped from a height of 16 m on a horizontal floor. If it rebounds to a height of

9 m after striking the floor, the coefficient of restitution between ball and floor is

a) 1/4

b) 2/3

c) 3/4

d) 4/3

Q10. A body is dropped from a height of 100 m and at the same time another body is projected vertically upward with a velocity of 10 m/sec. The two particles will

a) Never meet

b) Meet after 1 sec

c) Meet after 5 sec

d) Meet after 10 sec

Q11. A car goes round a curve of radius 100 m at 25 m/sec.the angle to the horizontal at which the road must be banked to prevent sideways friction on the car wheels is tan”1 x, where x is (assume g = 10 m/sec^2)

a) 3/8

b) 1/2

c) 9/5

d) 5/8

Q12. Two objects moving with uniform speeds are 5 m apart after 1 second when they move towards each other and are 1m apart when they move in the same direction. The speeds of the objects are

a) 2 m/sec and 2 m/sec

b) 3 m/sec and 2 m/sec

c) 3 m/sec and 3 m/sec

d) 4 m/sec and 6 m/sec

Q13. A bullet weighing 10 gm moves with a velocity of l km/sec. Its kinetic energy is

I) 5000 n.m

Ii) 5000 kg.m

Iii) 5000 j the correct answer is

a) Only (ii)

b) Both (i) and (iii)

c) Both (ii) and (iii)

d) All (i), (ii) and (iii)

Q14. The condilion for a lifting machine to be reversible is that its efficiency should be

a) Less than 50%

b) More than 50%

c) More than 66.67%

d) Equal to 100%

Q15. In a lifting machine a weight of 5 kn is lifted through 200 mm by an effort of 0.1 kn moving through 15 m. The mechanical advantage and velocity ratio of the machine are respectively

a) 50 and 75

b) 75 and 50

c) 75 and 75

d) 50 and 50

Q16. Free body diagram is an

a) Isolated joint with only body forces acting on it

b) Isolated joint with internal forces acting on it

c) Isolated joint with all the forces, internal as well as external, acting

d) None of the above

Q17. A system of copianar forces is in equilibrium when

a) Force polygon closes

b) Funicular polygon closes

c) Both force polygon” and funicular polygon close

d) All the forces are concurrent

Q18. The diagram showing the point of application and line of action of forces in their plane is called

a) Vector diagram

b) Space diagram

c) Force diagram

d) Funicular diagram

Q19. The graphical method of determining the forces in the members of a truss is based on

a) Method of joint

b) Method of section

c) Either method

d) None of the two methods

Q20. Coefficient of friction depends on

a) Nature of surfaces only

b) Area of contact only

c) Both (a) and (b)

d) None of the above

Part 5: Objective questions and answers of Applied Mechanics