86. The maximum wheel torque that can be completely braked is
    

1. 1. 200 N.m
      

   
   
   

   2. 382 N.m
      

   
   
   

   3. 604 N.m
      

   
   
   

   4. 844 N.m

   
   
   

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1. View Hint View Answer Discuss in Forum

   Braking torque = (T₁ – T₂) × r
   = (2101 – 200) × 2 = 382 N–m

   Correct Option: B

   Braking torque = (T₁ – T₂) × r
   = (2101 – 200) × 2 = 382 N–m

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87. 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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88. 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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89. 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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90. For the given statements :
    I. Mating spur gear teeth is an example of higher pair
    II. A revolute Joint is an example of lower pair Indicate the correct answer.
    

1. 1. Both I and II are false
      

   
   
   

   2. I is true and II is false
      

   
   
   

   3. I is false and II is true
      

   
   
   

   4. Both I and II are true
      

   
   
   

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1. View Hint View Answer Discuss in Forum

   Since higher pair has a line or point contact and lower pair has a surface of Area contact. Hence both are true. i.e., spur gear has line contact (Higher pair) and Revolute joint has surface contact (lower pair).
   

   Correct Option: D

   Since higher pair has a line or point contact and lower pair has a surface of Area contact. Hence both are true. i.e., spur gear has line contact (Higher pair) and Revolute joint has surface contact (lower pair).
   

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