A closely coiled helical spring of 20 cm mean diameter is having 25 coils of 2 cm diameter rod.The modulus of rigidity of the material is 107N/cm2. Then the stiffness of spring will be ………………..
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Solution
Three positions of quick return mechanism are shown below. In which of the cases does the coriolis component of acceleration exist ?
Select the correct answer :
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Solution
As we know that,
Coriolis component = – 2Ω × v ≅ 2 ωv
where, Ω = Angular velocity whose magnitude equal to rotation rate ω
v= velocity of the particle with respect to the rotating system
Now for situation (b), ω = 0 Coriolis component = 2ωv= 0
For, situation (c), v= 0
Coriolis component = 2ωv= 0
So, only situation(1) can exist/occur.
If a number of forces act on a rigid body,each force can be replaced by equal and parallel force acting through a fixed point, together with a couple. For the rigid body to be in equilibrium,
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Solution
Resultant force and couple become zero.
A square key of side d/4 is to be fitted on a shaft of diameter ‘d’ and in the hub of a pulley. If the material of key and shaft is same and both are equally strong in shear, then the lengh of the key will be :
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Solution
The length of key = pd/2
where, d= shaft diameter, and material of key and shaft is same.
Weldability of ferritic stainless steel used in automotive exhaust system is improved by selecting stainless steel electrode having low content of :
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Solution
By selecting stainless steel electrodes having low content of carbon,they do not generally tend to rusting or oxidation in the absence of protection of chromium.
A thick open ended cylinder as shown in figure,is made of a material with permissible normal and shear stresses 200 MPa and 100 MPa respectively. The ratio of permissible pressures based on the normal and shear stress is :
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Solution
The fixed investment for manufacturing a product is 1,40,000 in a specific year. The estimated sales for this year is 3,60,000. The variable cost/unit in ₹8 and unit price of the product in ₹27. Then, break even point for production will be …………….
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Solution
In a LPP which one of the following is correct for graphical method ?
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Solution
A point is not a solution to the problem in a feasible region for a LPP.
A cubical casting of size 9 mm is solidified in 27 seconds.The solidification time for similar cups of radius 12 mm will be ________
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Solution
A steel wire with E= 1.96 × 1011N/m2 of 3 mm diameter and is 40 mm long. It is fixed at upper end and carries amass ‘m’ kg at its lower end. If frequency of longitudinal vibrations is 4 cycle/sec, then the value of ‘m’ will be________
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Solution