# Recent questions and answers in Others

If a mass of moist air contained in a closed metallic vessel is heated, then its Relative humidity decreases. Relative humidity increases. Specific humidity increases. Specific humidity decreases.
Which one of the following statements about a phase diagram is INCORRECT? It indicates the temperature at which different phases start to melt Relative amount of different phases can be found under given equillibrium conditions It gives information on transformation rates Solid solubility limits are depicted by it
The figure below shows a symbolic representation of the surface texture in a perpendicular lay orientation with indicative values (I through VI) marking the various specifications whose definitions are listed below. P: Maximum waviness Height (mm); Q: Maximum Roughness Height (mm); R: Minimum Roughness Height (mm); S: Maximum ... -U, II-S, III-Q, IV-T, V-R, VI-P I-Q, II-U, III-R, IV-T, V-S, VI-P
In Materials Requirement Planning, if the inventory holding cost is very high and the set up cost is zero, which one of the following lot sizing approaches should be used? Economic Order Quantity Lot-for-Lot Base Stock Level Fixed Period Quantity, for $2$ periods
In the space above the mercury column in a barometer tube, the gauge pressure of the vapour is positive, but more than one atmosphere negative zero positive, but less than one atmosphere
The values of enthalpies at the stator inlet and rotor outlet of a hydraulic turbomachine stage are $h_1$ and $h_3$ respectively. The enthalpy at the stator outlet (or, rotor inlet) is $h_2$. The condition $(h_2-h_1)=(h_3-h_2)$ indicates that the degree of reaction of this stage is $\text{zero}$ $50 \%$ $75 \%$ $100 \%$
A beam of negligible mass is hinged at support $P$ and has a roller support $Q$ as shown in the figure. A point load of $1200 \: N$ is applied at point $R$. The magnitude of the reaction force at support $Q$ is _________ $N$.
A machine member is subjected to fluctuating stress $\sigma = \sigma_0 \cos (8 \pi t)$. The endurance limit of the material is $350$ MPa. If the factor of safety used in the design is $3.5$ then the maximum allowable value of $\sigma_0$ is _______ MPa. (round off to $2$ decimal places)
A bolt head has to be made at the end of a rod of diameter $d=12$ mm by localized forging (upsetting) operation. The length of the unsupported portion of the rod is $40$ mm. To avoid buckling of the rod, a closed forging operation has to be performed with a maximum die diameter of _______ mm.
Consider the following network of activities, with each activity named $\textbf{A – L}$, illustrated in the nodes of the network. The number of hours required for each activity is shown alongside the nodes. The slack on the activity $\textbf{L}$, is _______ hours.
In a furnace, the inner and outer sides of the brick wall $(k_1=2.5 \: \text{W/m.k})$ are maintained at $1100 ^\circ C$ and $700 ^\circ C$, respectively as shown in figure. The brick wall is covered by an insulating material of thermal conductivity $k_2$. The thickness of the ... the composite walls is $2500 \: W/m^2$. The value of $k_2$ is _______ $\text{W/m.K}$ (round off to one decimal place)
If a reversed Carnot cycle operates between the temperature limits of $27^\circ C$ and $-3^\circ C$, then the ratio of the COP of a refrigerator to that of a heat pump (COP of refrigerator / COP of heat pump) based on the cycle is __________ (round off to $2$ decimal places).
The directional derivative of $f(x,y,z) = xyz$ at point $(-1,1,3)$ in the direction of vector $\hat{i} – 2 \hat{j} +2 \hat{k}$ is $3\hat{i} – 3 \hat{j} - \hat{k} \\$ $- \dfrac{7}{3} \\$ $\dfrac{7}{3} \\$ $7$
The function $f(z)$ of complex variable $z=x+iy$, where $i=\sqrt{-1}$, is given as $f(z)=(x^3-3xy^2)+i \: v(x,y)$. For this function to be analytic, $v(x,y)$ should be $(3xy^2-y^3) +$ constant $(3x^2y^2-y^3) +$ constant $(x^3-3x^2 y) +$ constant $(3x^2y-y^3) +$ constant
A cantilever of length $l$, and flexural rigidity $EI$, stiffened by a spring of stiffness $k$, is loaded by a transverse force $P$, as shown. The transverse deflection under the load is $\dfrac{Pl^3}{3EI} \begin{bmatrix} \dfrac{3EI}{3EI+2kl^3} \end{bmatrix}$ ... $\dfrac{Pl^3}{3EI} \begin{bmatrix} \dfrac{3EI}{3EI+kl^3} \end{bmatrix}$
The sun (S) and the Planet (P) of an epicyclic gear train shown in the figure have identical number of teeth. If the sun (S) and the outer ring (R) gears are rotated in the same direction with angular speed $\omega_S$ and $\omega_R$, respectively, then the angular speed of the arm $AB$ ... $\dfrac{3}{4} \omega _R - \dfrac{1}{4} \omega _S$
A thin-walled cylinder of radius $r$ and thickness $t$ is open at both ends, and fits snugly between two rigid walls under ambient conditions, as shown in the figure. The material of the cylinder has Young's modulus $E$, Poisson's ratio $v$, and coefficient of thermal expansion $\alpha$. What is the ... $\Delta T = \big( v + \dfrac{1}{2} \big) \dfrac{pr}{ \alpha t E}$
A helical spring has spring constant $k$. If the wire diameter, spring diameter and the number of coils are all doubled then the spring constant of the new spring becomes $k/2$ $k$ $8k$ $16k$
Two rollers of diameters $D_1$ (in mm) and $D_2$ (in mm) are used to measure the internal taper angle in the V-groove of a machined component. The heights $H_1$ (in mm) and $H_2$ (in mm) are measured by using a height gauge after inserting the rollers into the same V-groove as shown in the ... $\sin \alpha = \dfrac{(H_1-H_2) }{ (D_1 - D_2)}$
The forecast for the monthly demand of a product is given in the table below: ... is made by using the exponential smoothing method. The exponential smoothing coefficient used in forecasting the demand is $0.10$ $0.40$ $0.50$ $1.00$
One kg of air in a closed system undergoes an irreversible process from an initial state of $p_1=1$ bar (absolute) and $T_1=27^\circ C$, to a final state of $p_2=3$ bar (absolute) and $T_2=127 ^ \circ C$. If the gas constant of air is $287 \: \text{J/kg.K}$ ... specific entropy (in $\text{J/kg.K}$) of the air in the process is $-26.3$ $28.4$ $172.0$ indeterminate, as the process is irreversible
For the integral $\displaystyle \int_0 ^{\pi/2} (8+4 \cos x) dx$, the absolute percentage error in numerical evaluation with the Trapezoidal rule, using only the end points, is ________ (round off to one decimal place).
A fair coin is tossed $20$ times. The probability that ‘head’ will appear exactly $4$ times in the first ten tosses, and ‘tail’ will appear exactly $4$ times in the next ten tosses is _________ (round off to $3$ decimal places)
A hollow spherical ball of radius $20$ cm floats in still water, with half of its volume submerged. Taking the density of water as $1000 \: kg/m^3$, and the acceleration due to gravity as $10 \: m/s^2$, the natural frequency of small oscillations of the ball, normal to the water surface is __________ radians/s (round off to $2$ decimal places)
Uniaxial compression test data for a solid metal bar of length $1$ m is shown in the figure. The bar material has a linear elastic response from $O$ to $P$ followed by a nonlinear response. The point $P$ represents the yield point of the material. The rod is ... the bar so that it does not buckle under axial loading before reaching the yield point is _______ mm ( round off to one decimal place)
The turning moment diagram of a flywheel fitted to a fictitious engine is shown in the figure. The mean turning moment is $2000$ Nm. The average engine speed is $1000$ rpm. For fluctuation in the speed to be within $\pm 2\%$ of the average speed, the mass moment of inertia of the flywheel is ________ $kg \cdot m^2$
A rigid block of mass $m_1=10$ kg having velocity $v_0=2 \: m/s$ strikes a stationary block of mass $m_2=30$ kg after traveling $1$ m along a frictionless horizontal surface shown in the figure. The two masses stick together and jointly move by a distance of $0.25$ m ... having a spring constant $k=10^5 \: N/m$. The maximum deflection of the spring is _________ cm (round off to $2$ decimal places)
A steel spur pinion has a module $(m)$ of $1.25$ mm, $20$ teeth and $20^\circ$ pressure angle. The pinion rotates at $1200$ rpm and transmits power to a $60$ teeth gear. The face width $(F)$ is $50$ mm, Lewis form factor $Y=0.322$ ... (round off to one decimal place). Lewis formula: $\sigma = \dfrac{K_vW^t}{FmY}$, where $W^t$ is the tangential load acting on the pinion.
A mould cavity of $1200 \: cm^3$ volume has to be filled through a sprue of $10$ cm length feeding a horizontal runner. Cross-sectional area at the base of the sprue is $2 \: cm^2$. Consider acceleration due to gravity as $9.81 \: m/s^2$. Neglecting frictional losses due to molten metal flow, the time taken to fill the mould cavity is ________ seconds (round off to $2$ decimal places)
A cylindrical bar with $200$ mm diameter is being turned with a tool having geometry $0 ^\circ - 9 ^\circ -7^ \circ - 8^ \circ - 15^ \circ - 30^ \circ - 0.05$ inch (coordinate system, ASA) resulting in a cutting force $F_{c1}$ ... $\displaystyle \bigg( \frac{F_{c2} - F_{c1}}{F_{c1}} \bigg) \times 100$, is ________ (round off to one decimal place)
There are two identical shaping machines $S_1$ and $S_2$. In machine $S_2$, the width of the workpiece is increased by $10\%$ and the feed is decreased by $10\%$, with respect to that of $S_1$. If all other conditions remain the same then the ratio of total time per pass in $S_1$ and $S_2$ will be _____ (round off to one decimal place).
A point $P'$ on a CNC controlled $XY$-stage is moved to another point $Q'$ using the coordinate system shown in the figure below and rapid positioning command $(G00)$ A pair of stepping motors with maximum speed of $800$ rpm, controlling both the $X$ and $Y$ motion of ... $P'$ to the point $Q'$ is _________ minutes (round off to $2$ decimal places).
In the following table, $x$ is a discrete random variable and $p(x)$ is the probability density. The standard deviation of $x$ is $\begin{array}{|c|c|c|c|} \hline x & 1 & 2 & 3 \\ \hline p(x) & 0.3 & 0.6 & 0.1 \\ \hline \end{array}$ $0.18$ $0.36$ $0.54$ $0.60$
One kg of air, initially at a temperature of $127^{\circ}C$ , expands reversibly at a constant pressure until the volume is doubled. If the gas constant of air is $287\: J/kg.K$, the magnitude of work transfer is ________ $kJ$ (round off to $2$ decimal places).
Multiplication of real valued square matrices of same dimension is associative commutative always positive definite not always possible to compute
The value of $\displaystyle{}\lim_{x \to \infty}\left ( \dfrac{1 -e^{-c\left ( 1-x \right )}}{1-x\:e^{-c\left ( 1-x \right )}} \right )$ is $\text{c} \\$ $\text{c + 1} \\$ $\dfrac{c}{c+1} \\$ $\dfrac{c+1}{c}$
The Laplace transform of a function $f(t)$ is $L( f )=\dfrac{1}{(s^{2}+\omega ^{2})}.$ Then, $f(t)$ is $f\left ( t \right )=\dfrac{1}{\omega ^{2}}\left ( 1-\cos\:\omega t \right ) \\$ $f\left ( t \right )=\dfrac{1}{\omega}\cos\:\omega t \\$ $f\left ( t \right )=\dfrac{1}{\omega}\sin\:\omega t \\$ $f\left ( t \right )=\dfrac{1}{\omega^{2}}\left ( 1-\sin\:\omega t \right )$
Which of the following function $f(z)$, of the complex variable $z,$ is NOT analytic at all the points of the complex plane? $f\left ( z \right )=z^{2}$ $f\left ( z \right )=e^{z}$ $f\left ( z \right )=\sin z$ $f\left ( z \right )=\log z$
The members carrying zero force (i.e. zero-force members) in the truss shown in the figure, for any load $P > 0$ with no appreciable deformation of the truss (i.e.with no appreciable change in angles between the members), are $BF$ and $DH$ only $BF, DH,$ and $GC$ only $BF, DH, GC, CD$ and $DE$ only $BF, DH, GC, FG$ and $GH$ only
A single-degree-of-freedom oscillator is subjected to harmonic excitation $F(t) = F_{0}\cos(\omega t)$ as shown in the figure. The non-zero value of $\omega$, for which the amplitude of the force transmitted to the ground will be $F_{0}$, is $\sqrt{\dfrac{k}{2m}} \\$ $\sqrt{\dfrac{k}{m}} \\$ $\sqrt{\dfrac{2k}{m}} \\$ $2\sqrt{\dfrac{k}{m}}$