46. Which kind of 4-bar mechanism is O₂ABO₄?

1. 1. Double crank mechanism

   
   
   

   2. Crank-rocker mechanism

   
   
   

   3. Double rocker mechanism

   
   
   

   4. Parallelogram mechanism

   
   
   

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1. View Hint View Answer Discuss in Forum

   AB = √(240)² + (160 − 60)²
   = 260 mm
   = = l_AO2 + l_O2O4 < l_AB + l_BO4
   = and O_{2O4 is fixed link. It will act as a crank-rocker mechanism}

   Correct Option: B

   AB = √(240)² + (160 − 60)²
   = 260 mm
   = = l_AO2 + l_O2O4 < l_AB + l_BO4
   = and O_{2O4 is fixed link. It will act as a crank-rocker mechanism}

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47. Match the following:
    Type of Mechanism
    P. Scott - Russel mechanism
    Q. Geneva mechanism
    R. Off-set slider-crank mechanism
    S. Scotch Yoke mechanism
    Motion achieved
    1. Intermittent motion
    2. Quick return motion
    3. Simple harmonic motion
    4. Straight line motion

1. 1. P-2 Q-3 R-1 S-4

   
   
   

   2. P-3 Q-2 R-4 S-1

   
   
   

   3. P-4 Q-1 R-2 S-3

   
   
   

   4. P-4 Q-3 R-1 S-2

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: C

   NA

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48. The mechanism used in a shaping machine is

1. 1. a closed 4-bar chain having 4 revolute pairs

   
   
   

   2. a closed 6-bar chain having 6 revolute pairs

   
   
   

   3. a closed 4-bar chain having 2 revolute and 2 sliding pairs

   
   
   

   4. an inversion of the single slider-crank chain

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: D

   NA

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49. A rod of length 1 m is sliding in a corner as shown in figure. At an instant when the rod makes an angle of 60 degrees with the horizontal plane., the velocity of point A on the rod is 1m/ s. The angular velocity of the rod at this instant is
    

1. 1. 2 rad/s

   
   
   

   2. 1.5 rad/s

   
   
   

   3. 0.5 rad/s

   
   
   

   4. 0.75 rad/s

   
   
   

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1. View Hint View Answer Discuss in Forum

   
   VA = O'A × ω
   1 = 1 cos 60° × ω
   ω = 2 rad/s

   Correct Option: A

   
   VA = O'A × ω
   1 = 1 cos 60° × ω
   ω = 2 rad/s

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50. Figure shows a quick return mechanism. The cranks OA rotates clockwise uniformly. OA = 2 cm, OO' = 4 cm. The ratio of time for forward motion to that for return motion is
    

1. 1. 0.5

   
   
   

   2. 2.0

   
   
   

   3. √2

   
   
   

   4. 1

   
   
   

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1. View Hint View Answer Discuss in Forum

   Ratio of time of forward motion to return motion
   

   =	180 + 2α	=	180 + 60	=	240	= 2
   	180 − 2α		180 − 60		120

   
   (Given OD = 2 cm, OO ' = 4 cm, sin α = 2/4 = 0.5 ⇒ α = 30°)

   Correct Option: B

   Ratio of time of forward motion to return motion
   

   =	180 + 2α	=	180 + 60	=	240	= 2
   	180 − 2α		180 − 60		120

   
   (Given OD = 2 cm, OO ' = 4 cm, sin α = 2/4 = 0.5 ⇒ α = 30°)

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