Applied Mechanics 6

Objective Questions and Answers of Civil Engineering: Applied Mechanic 6

Subject: Applied Mechanics 6

Part 6: Objective questions and answers of Applied Mechanics

Q1. The dimensions of centrifugal force are

a) M1 l2 t2

b) M’l’t1

c) M’l’t2

d) M’l-‘t2

Q2. In SI units, the units of force and energy are respectively

a) Newton and watt

b) Dyne and erg

c) Newton and joule

d) Kg-wt and joule

Q3. Which of the following is a scalar quantity?

a) Energy

b) Momentum

c) Torque

d) Impulse

Q4. A rope is wrapped twice around a rough pole with a coefficient of friction ‘a . It is subjected to a force fj at one end and a gradually increasing force f2 is applied at the other end till the rope just starts slip-ping. At this instant the ratio of f2 to fi is

a) 1

b) E2*

c) E4*

d) E*72

Q5. If a body is lying on a plane whose inclination with the horizontal is less than the angle of friction, then?

I) a force is required to move the body upwards

Ii) A force is required to move the body downward

Iii) The body will not be in equilibrium the correct answer is

a) Only (i)

b) Only (ii)

c) Both (i) and (ii)

d) Both (i) and (iii)

Q6. Intrinisic equation of catenary is given by

a) S = c tan q>

b) S = c cos cp

c) S = c sin cp

d) S = c cot <p

Where c is some constant.

Q7. Cartesian form of the equation of catenary is

a) Y = c cosh x/c

b) Y = c sinh x/c

c) Y = c tan x/c

d) Y = c sin”1 x/c

Q8. Minimum pull in a suspended cable with supports at two ends is equal to

a) Horizontal thrust

b) Support reactions

c) Resultant of horizontal thrust and support reaction

d) Half the weight of the cable

Q9. The maximum pull in a cable, carrying a uniformly distributed load and supported at two ends which are at the same level, is at

a) Supports

b) Quarter span

c) Mid span

d) None of the above

Q10. A particle is dropped from a height of 3 m on a horizontal floor, which has a coefficient of restitution with the ball of 1/2. The height to which the ball will rebound after striking the floor is

a) 0.5 m

b) 0.75 m

c) 1.0 m

d) 1.5 m

Q11. Two balls of masses 3 kg and 6 kg are moving with velocities of 4 m/sec and 1 m/sec respectively, towards each other along the line of their centers. After impact the 3 kg ball comes to rest. This can happen only if the coefficient of restitution between the balls is

a) 2/3

b) 1/5

c) 3/5

d) 1/3

Q12. When a body slides down an inclined surface, the acceleration of the body is given by

a) G

b) Gsing

c) G cos 6

d) G tan 6

Q13. A shell travelling with a horizontal velocity of 100 m/sec explodes and splits into two parts, one of mass 10 kg and the other of 15 kg. The 15 kg mass drops vertically downward with initial velocity of 100 m/sec and the 10 kg mass begins to travel at an angle to the horizontal of tan”1 x, where x is

a) 3/4

b) 4/5

c) 5/3

d) 3/5

Q14. A shell of mass 100 kg travelling with a velocity of 10 m/sec breaks into two equal pieces during an explosion which provides an extra kinetic energy of 20000 joules. If the pieces continue to move in the same direction as before, then the speed of the faster one must be

a) 20 m/sec

b) 30 m/sec

c) 40 m/sec

d) 50 m/sec

Q15. If a flywheel increases its speed from 10 rpm to 20 rpm in 10 seconds, then its angular acceleration is

d) None of the above

Q16. The angular speed of a car taking a circular turn of radius 100 m at 36 km/hr will be

Q17. A stone was thrown vertically upwards from the ground with a velocity of 50 m/sec.

After 5 seconds another stone was thrown vertically upwards from the same place. If both the stones strike the ground at the same time, then the velocity with which the second stone was thrown should be (assume g = 10 m/sec^2)

a) 15 m/sec

b) 25 m/sec

c) 40 m/sec

d) 50 m/sec

Q18. In a lifting machine with efficiency 60%, an effort of 200 n is required to raise a load of

6 kn. The velocity ratio of the machine is

a) 30

b) 50

c) 60

d) 80

Q19. A system of copianar forces acting on a rigid body can be reduced to

a) One force only

b) One couple only

c) One force and one couple only

d) None of the above

Q20. Force polygon method is applicable for

a) Any copianar force system

b) A system of parallel forces only

c) Concurrent copianar force system

d) Non-concurrent copianar force system

Part 6: Objective questions and answers of Applied Mechanics