41. In a bolted Joint two smooth members are connected with an axial tightening force of 2200 N. If the bolt used has metric threads of 4 mm pitch, the torque required for achieving the tightening force is
    
    

1. 1. 0.7 Nm
      

   
   
   

   2. 1.0 Nm
      

   
   
   

   3. 1.4 Nm
      

   
   
   

   4. 2.8 Nm
      

   
   
   

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1. View Hint View Answer Discuss in Forum

   Tightening force = 2200 N
   Pitch = 4 mm = 0.004 m
   

   Torque = Tightening force ×	0.004	= 1.4 N-m
   	2π

   Correct Option: C

   Tightening force = 2200 N
   Pitch = 4 mm = 0.004 m
   

   Torque = Tightening force ×	0.004	= 1.4 N-m
   	2π

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42. A bolted Joint is shown below. The maximum shear stress, in MPa, in the bolts at A and B, respectively are
    
    

1. 1. 242.6 , 42.5
      

   
   
   

   2. 42.5 , 242.6
      

   
   
   

   3. 42.5 , 42.5
      

   
   
   

   4. 60.15 , 343.64

   
   
   

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1. View Hint View Answer Discuss in Forum

   FA = FB = FC =	10	kN
   	3

   
   

   FA =	P.e.r	=	10 × 103 × 150 × 40
   	rA² + rB² + rC²		40² + 0² + 40²

   
   F'_A = 18.75 kN = F'_C
   Shear load at A and C
   F_R = √(F_A)² + (F'_A)² = √(3.33)² + (18.75)²
   F_R = 19.04 KN
   

   τmax =	19.04 × 103
   	(π / 4) × 102

   
   ( τ_max )A,C = 242.5 MPa
   ( τ_max )B = 42.44 MPa
   

   Correct Option: A

   FA = FB = FC =	10	kN
   	3

   
   

   FA =	P.e.r	=	10 × 103 × 150 × 40
   	rA² + rB² + rC²		40² + 0² + 40²

   
   F'_A = 18.75 kN = F'_C
   Shear load at A and C
   F_R = √(F_A)² + (F'_A)² = √(3.33)² + (18.75)²
   F_R = 19.04 KN
   

   τmax =	19.04 × 103
   	(π / 4) × 102

   
   ( τ_max )A,C = 242.5 MPa
   ( τ_max )B = 42.44 MPa
   

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43. Which one of the following is used to convert a rotational motion into a translational motion?
    

1. 1. Bevel gears
      

   
   
   

   2. Double helical gears
      

   
   
   

   3. Worm gears
      

   
   
   

   4. Rack and pinion gears

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA
   

   Correct Option: D

   NA
   

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44. In a band brake the ratio of tight side band tension to the tension on the slack side is 3. If the angle of overlap of band on the drum is 180°, the coefficient of friction required between drum and the band is
    

1. 1. 0.20
      

   
   
   

   2. 0.25
      

   
   
   

   3. 0.30
      

   
   
   

   4. 0.35

   
   
   

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1. View Hint View Answer Discuss in Forum

   Given ,	Tension in tight side	=	T1	= 3
   	Tension is slack side		T2

   
   

   	T1	= eμ θ
   	T2

   
   where, θ = angle of overlap = 180 = π radians
   ∴ 3 = e^{μ θ}
   ln(3) = μ θ
   

   ∴ μ =	1	ln(3) = 0.35
   	π

   Correct Option: D

   Given ,	Tension in tight side	=	T1	= 3
   	Tension is slack side		T2

   
   

   	T1	= eμ θ
   	T2

   
   where, θ = angle of overlap = 180 = π radians
   ∴ 3 = e^{μ θ}
   ln(3) = μ θ
   

   ∴ μ =	1	ln(3) = 0.35
   	π

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45. The maximum tension that can be generated in the band during braking is
    

1. 1. 1200 N
      

   
   
   

   2. 2110 N
      

   
   
   

   3. 3224 N
      

   
   
   

   4. 4420 N

   
   
   

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1. View Hint View Answer Discuss in Forum

   θ = 270°
   μ = 0.5
   Taking moment about 0,
   
   ∑ M₀ = 0
   ⇒ T₂ × 1 - 100 × 2 = 0
   T₂ = 200 N
   

   	T1	= eμ θ
   	T2

   
   

   	T1	= e0.5 × (3π / 2)
   	T2

   
   T₁ = 2110 N
   

   Correct Option: B

   θ = 270°
   μ = 0.5
   Taking moment about 0,
   
   ∑ M₀ = 0
   ⇒ T₂ × 1 - 100 × 2 = 0
   T₂ = 200 N
   

   	T1	= eμ θ
   	T2

   
   

   	T1	= e0.5 × (3π / 2)
   	T2

   
   T₁ = 2110 N
   

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