# Engineering Mechanics 3

First Year Engineering Common to all Branches: Engineering Mechanics 3

Subject: Engineering Mechanics 3

Part 3: List for questions and answers of Engineering Mechanics

Q1. The rate of change of displacement of a body is called
a) Velocity
b) Acceleration
c) Momentum
d) None of these

Q2. The efficiency of a screw jack is maximum, when(where Fi = Angle of friction.)
a) α = 45° + φ/2
b) α = 45° – φ/2
c) α = 90° + φ
d) α = 90° – φ

Q3. The periodic time (T) is given by  (where w = Angular velocity of particle in rad / s.)
a) ω/2π
b) 2π/ω
c) 2π × ω
d) π/ω

Q4. The resultant of two forces P and Q (such that P > Q) acting along the same straight line, but in opposite direction, is given by
a) P + Q
b) P – Q
c) P / Q
d) Q / P

Q5. The law of motion involved in the recoil of gun is
a) Newton’s first law of motion
b) Newton’s second law of motion
c) Newton’s third law of motion
d) None of these

Q6. The range of projectile will be maximum for a given velocity of projectile, when the angle of projection (p) is
a) p/2
b) 30° + p/2
c) 45° + p/2
d) 60° + p/2

Q7. When two elastic bodies collide with each other,
a) The two bodies will momentarily come to rest after collision
b) The two bodies tend to compress and deform at the surface of contact
c) The two bodies begin to regain their original shape
d) All of the above

Q8. The maximum velocity of a particle moving with simple harmonic motion is
a) ω
b) ωr
c) ω2r
d) ω/r

Q9. The unit of power in S.I. units is
a) Horsepower
b) Joule
c) Watt
d) Kg-m

Q10. The resultant of two equal forces P making an angle θ, is given by
a) P sin θ /2
b) 2 P cos θ /2
c) P tan θ /2
d) P cot θ /2

Q11. The force, by which the body is attracted, towards the centre of the earth, is called
a) Impulsive force
b) Mass
c) Weight
d) Momentum

Q12. The power developed by a body acted upon by a torque T newton metre (N – m) and revolving at ω radian/s is given by
a) T.ω (in watts)
b) T.ω/60 (in watts)
c) T.ω/75 (in kilowatts)
d) T.ω/4500 (in kilowatts)

Q13. The velocity ratio of a first system of pulleys with 4 pulleys is
a) 4
b) 8
c) 16
d) 20

Q14. The forces which do not meet at one point and their lines of action do not lie on the same plane are known as
a) Coplaner concurrent forces
b) Coplaner non-concurrent forces
c) Non-coplaner concurrent forces
d) None of these

Q15. The forces, which meet at one point and their lines of action also lie on the same plane, are known as
a) Coplaner concurrent forces
b) Coplaner non-concurrent forces
c) Non-coplaner concurrent forces
d) Non-coplaner non-concurrent forces

Q16. The unit of energy in S.I. units is
a) Dyne
b) Watt
c) Kg-m
d) Joule

Q17. The angle of inclination of the plane at which the body begins to move down the plane, is called
a) Angle of friction
b) Angle of repose
c) Angle of projection
d) None of these

Q18. In a single threaded worm and worm wheel, the number of teeth on the worm is 50. The diameter of the effort wheel is 100 mm and that of load drum is 50 mm. The velocity ratio is
a) 50
b) 100
c) 150
d) 200

Q19. The total motion possessed by a body, is called
a) Impulsive force
b) Mass
c) Weight
d) Momentum

Q20. If P is the force acting on the body, m is the mass of the body and a is the acceleration of the body, then according to Newton’s second law of motion,
a) P + m.a = 0
b) P – m.a = 0
c) P x m.a = 0
d) P/m.a = 0

Part 3: List for questions and answers of Engineering Mechanics

Q1. Answer: a

Q2. Answer: b

Q3. Answer: b

Q4. Answer: b

Q5. Answer: c

Q6. Answer: c

Q7. Answer: d

Q8. Answer: b

Q9. Answer: c

Q10. Answer: b

Q11. Answer: c

Q12. Answer: a

Q13. Answer: c

Q14. Answer: d

Q15. Answer: a

Q16. Answer: d

Q17. Answer: a

Q18. Answer: b

Q19. Answer: d

Q20. Answer: b