For conduction through a spherical wall with constant thermal conductivity and with inner side temperature greater than outer wall temperature, if heat transfer is one-dimensional,then the type of temperature distribution is:
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Solution
For conduction through spherical wall,thermal conductivity (K) = constant
ti > t0
where, ti= inner temperature
to= outer temperature
For the above conditions, for one-dimensional heat conduction, temperature distribution will be hyperbolic.
Tds equation can be expressed as:
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Solution
A body of mass 8 kg is supported on a spring of stiffness 200N/m and has a dashpot connected to it which produces are sistance of 0.003 N at a velocity of 2 cm/s. After 6 cycles,the reduction ratio of amplitude of vibration will be ________.
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Solution
The distance covered by a body of mass 2 kg with respect to time is given as:
s = 6t3– 4t2+ 9
where, S =distance, t = time
Then,the acceleration and the driving force of the body after 9 seconds will be ________.
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Solution
Actual demand for the first period is 92 units and forecast was 96 units. If exponential smoothing factor is 0.5, then the forecast for the next period will be ________.
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Solution
Given: Actual demand for first period (Dt–1)= 92 units
Forecast (St–1) = 96 units.
Exponential smoothing factor (a) = 0.5
Forecast for next period (St)=αDt–1+ (1 – α)St–1
= 0.5 × 92 + (1 – 0.5) 96
= 46 + 48 = 94 units
In a blanking operation, the maximum punch load in 6 × 106 N. If the percentage penetration is 40% and thickness of plate is 9mm, then the work done during the shearing operating will be ________.
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Solution
The length of a cylindrical shaped casting is equal to diameter.The solidification time for cylindrical casting is 25 min. If the aspect ratio and material is kept same, then solidification time for a 8 timer heavier cylinder will be________.
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Solution
Miller indices for the crystallographic plane shown in figure are given as:
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Solution
Intercepts on x, y and z axis.
Ix= 1, Iy= ∞, I2 = 1
Taking reciprocals,h=1⁄1=1, K=1⁄∞= 0, 1=1⁄1=1
thus, Miller indices are (h, k, l) = (101)
A cube with a side length of 1 cm is heated uniformly 1°C above the room temperature and all the sides are free to expand. If thermal expansion coefficient is a/°C, then in crease in volume of the cube will be ________.
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Solution
As we know that,
change in dimension (Δl) = l αl ΔT
where, ΔT = change in temperature
αl =coefficient of thermal expansion
l= side length
Given:l = 1 cm, ΔT = 1°C, αl= α
Change in side length (Δl) =1 × α × 1 = a
Change/increase in volume = 3αcm3
Match List-I with List-II
List-I List-II
(a)Unwin’s formula 1.Bearing
(b)Wahl factor 2.Rivetr
(c)Reynold’s equation 3.Gears
(d)Lewis form factor 4.Springs
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Solution
unwin’s formula = Rivets
wahl factor= springs
Reynold’s equation= Bearing
liwis term factor = Gears