Dynamics Of Machines Set 1

Mechanical Engineering

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This set of Dynamics of Machines Multiple Choice Questions & Answers (MCQs) focuses on Dynamics Of Machines Set 1

Q1 | Which of the following is incorrect regarding inertia force?
  • imaginary force
  • acts upon a rigid body
  • brings the body to equilibrium
  • same direction as of accelerating force
Answer: same direction as of accelerating force
Q2 | Inertia torque acts in the same direction as the accelerating couple?
  • true
  • false
Answer: false
Q3 | If a force has a line of action at a distance h from the centre of gravity, then the value of h is given by            
  • i. α/f
  • i. α/m.g
  • i/m.k
  • m.k/i
Answer: i. α/f
Q4 | D-Alembert’s principle is used for which of the following?
  • change static problem into a dynamic problem
  • change dynamic problem to static problem
  • to calculate moment of inertia of rigid bodies
  • to calculate angular momentum of a system of masses
Answer: change dynamic problem to static problem
Q5 | 2 D ALEMBERT'S PRINCIPLE - DYNAMIC ANALYSIS IN RECIPROCATING ENGINES
  • reversed effective force
  • net force
  • coriolis force
  • resultant force
Answer: reversed effective force
Q6 | Why the inertia torque acts in the opposite direction to the accelerating couple?
  • bring the body in equilibrium
  • to reduce the accelerating torque
  • acts as a constraint torque
  • increase the linear acceleration
Answer: bring the body in equilibrium
Q7 | A body remains in equilibrium if                  
  • inertia force is applied in the same direction to the resultant force
  • inertia force is applied in the direction opposite to the resultant force
  • inertia force is applied in the direction perpendicular to the resultant force
  • inertia force is applied in the direction parallel to the resultant force
Answer: inertia force is applied in the direction opposite to the resultant force
Q8 | Inertia force and the reversed effective force are the same.
  • true
  • false
Answer: true
Q9 | In the following picture the G is the center of gravity, the quantity h is known as the “offset”. I is the moment of inertia and k is the radius of gyration. Offset’s value is given by?
  • i.α/f
  • i.α/m.g
  • i/m.k
  • m.k/i
Answer: i.α/f
Q10 | Considering a four bar chain with each link having linear and angular acceleration, applying D-Alembert’s principle will never result in which of the following member?
  • 2- force member
  • 3- force member
  • 4 – force member
  • non accelerating member
Answer: 2- force member
Q11 | The net force acting on the crosshead pin is known as                      
  • crank pin effort
  • crank effort
  • piston effort
  • shaft effort
Answer: piston effort
Q12 | Piston effort acts along the line of stroke.
  • true
  • false
Answer: true
Q13 | In a horizontal engine, reciprocating parts are accelerated when the piston moves from
  • tdc to bdc
  • bdc to tdc
  • midway to tdc
  • bdc to midway
Answer: tdc to bdc
Q14 | In a horizontal engine, reciprocating parts are retarded when the piston moves from
  • tdc to bdc
  • bdc to tdc
  • midway to tdc
  • bdc to midway
Answer: bdc to tdc
Q15 | When the piston is accelerated, the piston effort is given by which of the following the equation?
  • f(l) – f(i)
  • f(l) + f(i)
  • f(l) ± f(i)
  • f(l) – f(i) + r(f)
Answer: f(l) + f(i)
Q16 | In the presence of frictional resistance, the expression for piston effort is                    
  • f(l) – f(i)
  • f(l) + f(i)
  • f(l) ± f(i) – r(f)
  • f(l) – f(i) + r(f)
Answer: f(l) ± f(i) – r(f)
Q17 | Crank effort is the product of crank pin radius and                
  • thrust on sides
  • crankpin effort
  • force acting along connecting rod
  • piston effort
Answer: crankpin effort
Q18 | In a horizontal engine, the weight of the reciprocating parts also add/subtract to the piston effort.
  • true
  • false
Answer: false
Q19 | For the given data of an Internal combustion engine : Mass of parts = 180 kg bore = 175 mm, length of stroke = 200 mm, engine speed = 500 r.p.m., length of connecting rod = 400 mm and crank angle = 60° from T.D.C, find the inertia force.
  • 17.56 n
  • 19.2 n
  • 18.53 n
  • 18.00 n
Answer: 18.53 n
Q20 | 45 N/mm2. The connecting rod length between centres is 1.2 m and the cylinder bore is 0.5 m. If the engine runs at 250 r.p.m. and if the effect of piston rod diameter is neglected, calculate the net load on piston.
  • 88000 n
  • 90560 n
  • 78036 n
  • 88357 n
Answer: 88357 n
Q21 | 2 m and the cylinder bore is 0.5 m. engine runs at 250 r.p.m & 30° from T.D.C. Find the piston effort.
  • 32.4 kn
  • 35.2 kn
  • 37.3 kn d) 40.2 n
Answer: 37.3 kn d) 40.2 n
Q22 | Multi cylinder engines are usually placed at an equal inclination to each other.
  • true
  • false
Answer: true
Q23 | For a multicylinder engine, the coefficient of fluctuation of speed would vary with
  • number of cylinders
  • remains unaffected
  • length of connecting rod
  • input temperature
Answer: remains unaffected
Q24 | For a 4 cylinder engine, if the minimum speed of the engine is half the maximum speed, then coefficient of fluctuation is
  • 0.5
  • 1.5
  • 2
  • 0.66
Answer: 0.66
Q25 | In the turning moment diagram of a multicylinder engine, the work done during exhaust stroke is by              
  • the gases
  • on the gases
  • piston wall
  • valve
Answer: on the gases
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