36. Two shafts A and B are made of the same material. The diameter of shaft B is twice that of shaft A The ratio of power which can be transmitted by shaft A to that of shaft B is
    

1. 1. 1

      2

      
      

   
   
   

   2. 1

      4

      
      

   
   
   

   3. 1

      8

      
      

   
   
   

   4. 1

      16

   
   
   

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1. View Hint View Answer Discuss in Forum

   TA =	π	× d3τ
   	16

   
   

   TB =	π	× (2d)3τ
   	16

   
   

   	PA	=	TA	=	1
   	PB		TB		8

   Correct Option: C

   TA =	π	× d3τ
   	16

   
   

   TB =	π	× (2d)3τ
   	16

   
   

   	PA	=	TA	=	1
   	PB		TB		8

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37. Torque to weight ratio for a circular shaft transmitting power is directly proportional to the
    

1. 1. square root of the diameter
      

   
   
   

   2. diameter
      

   
   
   

   3. square of the diameter
      

   
   
   

   4. cube of the diameter

   
   
   

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1. View Hint View Answer Discuss in Forum

   T =	π	d3τ
   	16

   
   

   w = π	d2	ρl
   	4

   
   

   	T	∝ d
   	w

   Correct Option: B

   T =	π	d3τ
   	16

   
   

   w = π	d2	ρl
   	4

   
   

   	T	∝ d
   	w

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38. A large uniform plate containing a rivet hole subjected to uniform uniaxial tension of 95 MPa. The maximum stress in the plate is
    
    

1. 1. 100 MPa
      

   
   
   

   2. 285 MPa
      

   
   
   

   3. 190 MPa
      

   
   
   

   4. Indeterminate

   
   
   

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1. View Hint View Answer Discuss in Forum

   Max Stress =	Avg. Force
   	Min. Area

   
   

   =	95 × 10 × t	= 100 MPa
   	(10 - 0.5)t

   Correct Option: A

   Max Stress =	Avg. Force
   	Min. Area

   
   

   =	95 × 10 × t	= 100 MPa
   	(10 - 0.5)t

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39. The outside diameter of a hollow shaft that is twice its inside diameter the ratio of its torque carrying capacity to that of a solid shaft of the same material and the same outside diameter is
    

1. 1. 15

      16

      
      

   
   
   

   2. 3

      4

      
      

   
   
   

   3. 1

      2

      
      

   
   
   

   4. 1

      16

   
   
   

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1. View Hint View Answer Discuss in Forum

   Thollow =	π		d4 -	d4		2τ	......(1)
   	32			16		d

   
   

   Tsolid =	π	d3τ .......(2)
   	16

   
   By dividing (1) with (2)
   

   	Thollow	=	15
   	Tsolid		16

   Correct Option: A

   Thollow =	π		d4 -	d4		2τ	......(1)
   	32			16		d

   
   

   Tsolid =	π	d3τ .......(2)
   	16

   
   By dividing (1) with (2)
   

   	Thollow	=	15
   	Tsolid		16

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40. The expected life of a ball bearing subjected to a load of 9800 N and working at 1000 rpm is 3000 hours. What is the expected life of the same bearing for a similar load of 4900 N and speed of 2000 rpm?
    

1. 1. Unchanged
      

   
   
   

   2. 12000 hours
      

   
   
   

   3. 1500 hours
      

   
   
   

   4. 6000 hours

   
   
   

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1. View Hint View Answer Discuss in Forum

   L (P)³ = constant
   

   	L1	=		P2		3
   	L2			P1

   
   

   ⇒	1000 × 60 × 3000	=		4900		3
   	2000 × 60 × t2			9800

   
   t₂ = 12000 hours
   

   Correct Option: B

   L (P)³ = constant
   

   	L1	=		P2		3
   	L2			P1

   
   

   ⇒	1000 × 60 × 3000	=		4900		3
   	2000 × 60 × t2			9800

   
   t₂ = 12000 hours
   

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