A body is resting on a plane inclined at angle of $$30^\circ$$ to horizontal. What force would be required to slide it down, if the coefficient of friction between body and plane is 0.3?
ISRO Scientist or Engineer Refrigeration & Air-Conditioning 2015
For the following questions answer them individually
Compression members tend to buckle in the direction of
A fluid jet discharging from 150 mm diameter orifice has a diameter of 100 mm at its vena contracta. The coefficient of contraction is
The escape velocity on the surface of the earth is
The heat to be supplied to a Carnot engine operating between 800 and 400 K and producing 100 kJ of work, is
A piece of wood having weight of 10 kg floats in water with 60% of its volume under the liquid. Determine the specific Gravity of wood.
If all the dimension of a prismatic bar be increased in the ratio of k : 1, then maximum stress producedin the bar due to its own weightwill increase in the following ratio
A house requires 60M cal/hr in winter for heating. Heat pump absorbs heat from cold air outside and requires 8M cal/hr of work. The COP will be
A body moves, from rest with a constant acceleration of 5 m per sec”. The distance covered in 10 sec is most nearly
A cold storage plant of 20 tonne of refrigerator capacity operates between 200 and 300 k. The power required to run the plant if the plant has half COP of a Carnot cycle (Tonne of refrigerator = 3.5 kW) is
Two cars are 10 km apart and moving in the same direction at speed of 40 km/hr. A car moving in opposite direction meets these cars at interval of 10 minutes. At what speed the
other car is moving?
Diagram factor is defined as the ratio of
A liquid compressed in a cylinder has a volume of 0.04 m$$^3$$ at 100 kg/cm$$^2$$ and a volume of 0.39 m$$^3$$ at 200 kg/cm$$^2$$. The bulk modulusofelasticity of liquid is
The equation $$\left\{p + \frac{a}{v^2}\right\}(v - b) = R$$ is known as
Tumblingis the process of
In Electrolux refrigerator
According to theorem of perpendicular axes, if $$I_{xx}$$ and $$I_{yy}$$ be the M.I of a lamina about xx and yy axis, then M.I. of the lamina about axis zz, which is perpendicular to xx and yy, equal to
A perfect gas at $$27^\circ C$$ is heated at constant pressuretill its volume is double. The final temperature is
The value of acceleration due to gravity at moon is $$\frac{g}{6}$$, where g is the value of acceleration due to gravity at earth. The valueof frequency of oscillation of simple pendulum on moon as compared to earth will be
Maximum shear stress in a Mohr’s circle is
Froude numberis the ratio of inertial force to
Proof resilience per unit volumeof a material is known as
Cooling rangein cooling toweris the
The vapour compression refrigerator employs the following cycle
A certain high tensile strength steel has a modulus of elasticity of $$2 \times 10^6 kg/cm^2$$ and a yield point stress of 6,000 kg/cm$$^2$$. Find the minimum limiting value of the slenderness ratio for which Euler’s equation is valid
The ratio of central deflection due to a central load in the case of a beam freely supported at both ends to the beam fixed at both ends will be
A framed structure is perfect if it contains members equal to
where n = numberof joints in a frame.
Prandtl number is expressed by
Coining is the operation of
Moment of inertia of a square of side d about the diagonal is
If the velocity of projection is u m/sec and the angle of projection is. $$\alpha^\circ$$, the maximum height of the projectile on a horizontal plane is
If air is heated without changing its moisture content, the dew point will
In a tensile testing experiment on a specimen of 1 cm$$^2$$ area, the maximum load observed was 5 tonnes and neck area 0.25 cm$$^2$$. The ultimate tensile strength of specimenis
For a given material assume, Young’s modulus E = 300 GN/m$$^2$$ and modulus of rigidity G = 150 GN/m$$^2$$. Its bulk modulus K will be
A steel wire hangs vertically under its own weight. If its density is 10000 kg/m$$^3$$ and allowable stress is 3000 kg/cm$$^2$$ then how muchlength it can sustain.
Laser is produced by
M.I. of a triangular section of base a and height h about an axis passing through its c.g. and parallel to base is
To convert volumetric analysis to gravimetric analysis, the relative volume of each constituent of the flue gases is
Film coefficient is defined as
The longitudinal stress induced in a thin walled cylindrical vessel is
Electron beam machining processis suitable for the following type of material
The length of a second’s pendulum is
The period of oscillation of a simple pendulum depends on
A spherical vessel with an inside diameter of 2 m is made of material having an allowable stress in tension of 500 kg/cm$$^2$$. The thickness of a shell to withstand a pressure of 50 kg/cm$$^2$$ should be
For best hydraulic rectangular cross-section of an open channel, its depth should be equal to
Compare the strengths of solid and hollow shafts both having outside diameter D and hollow shaft having inside diameter of $$\frac{D}{2}$$ in torsion. The ratio of strength of solid to hollow shafts in torsion will be
Following gases are used in Tungsten inert gas welding
A heat engine is supplied heat at the rate of 30,000 J/s and gives an output of 9 kW. The thermal efficiency of engine will be
If a body is transmitting torque T kgm at angular speed of $$\theta$$ radians/sec, then h.p. transmitted will be
The critical radius of insulation for a spherical shell is
When a body slides down a surface inclined $$\theta$$ to horizontal, the acceleration (f) of the body is given by
If $$\sigma_1$$ and $$\sigma_2$$ be the major and minor tensile stresses, then maximum value of tangential stress is equal to
The pressure in the air space above an oil (sp. Gravity 0.7) surface in a tank is 0.1 kg/cm$$^2$$. The pressure at 5 m below theoil surface will be
Thermal weldingis a form of
The ratio of heat flow $$\frac{Q_1}{Q_2}$$ from two walls of same thickness having their thermal conductivities as $$K_1 = 2K_2$$ will be
A Carnot engine has an efficiency of 0.5. The COP ofrefrigerant working with the same temperature limit is
Slack represent the difference between the
A refrigerator operates on a reverse Carnot eycle between 900 and 300 k. If heat at the rate of 3 kJ/s is extracted from the low temperature space, then the power required to drive the refrigerator
If V is the mean velocity of flow, then according to Darcy-Weisbach equation for pipe flow energy loss over a length of pipeline is proportional to
40% of incident radiant energy on the surface of a thermally transparent bodyis reflected back. Ifthe transmissivitiy of the body be 0.15, then the emissivity of surface is
Study showed the percentage of occurrence of an activity as 50%. The number of observations for 95% confidence level and an accuracy of $$\pm$$2% is
1 m$$^3$$ of air at a pressure of 10 kg/cm$$^2$$ is allowed to expand freely to a volume of 10 m$$^3$$. The work done will be
Suppose that a particle moves on a coordinate line so that its velocity at time t is $$v(t) = t^2 - 2t$$ m/s. The displacementofthe particle during time interval $$0 \leq t \leq 3$$ is
Approach of cooling tower means
Which of the following is not the intensive property?
A carnot cycle consists of
Two loads P act at right angles to one another at the free end of a cantilever beam having square cross-section $$d \times d$$ and length l on the vertical and horizontal faces. Maximum bending stress in the beam will be equal to
The head loss due to sudden expansion assuming incompressible flow is expressed by
PERT has the following time estimate
‘Two plane slabs of equal areas and conductivities in the ratio 1 : 2 are held together and temperature in between surface ends are $$t_1$$ and $$t_2$$. If junction temperature in between two surfaces is desired to be $$\frac{t_1 + t_2}{2}$$, then their thicknesses should be in the ratio of
300 kJ/s of heat is supplied at constant temperature of 500 k to a heat engine. The heat rejection takes place at 300 K. The following results are obtained (a) 210 kJ (b) 180 kJ
(c) 150 kJ. Identify whether result is a reversible cycle, irreversible cycle or impossible cycle respectively
If cube root of unity are $$1, w, w^2$$ then the roots of equation $$(x - 1)^3 + 8 = 0$$ are
If $$1, w, w^2$$ are cube roots of unity then the value of
Three houses are available in a locality. Three persons apply for the houses. Each applies for one house without consulting others. The probability that all the three apply for the same house is
The rank of the matrix $$A = \begin{bmatrix}-2 & 4 & 2\\3 & -4 & -1\\4 & -3 & 1 \end{bmatrix}$$ is
If $$3e^x \tan ydx + (1 - e^x) \sec^2 ydy = 0$$, then $$y$$ is
Which of the following represents a wave equation?
$$1 + \frac{x^2}{2!} + \frac{x^4}{4!} + \frac{x^6}{6!} + .........$$ stands for
$$\int \sec x dx$$ is
Inverse Laplace transform of $$\frac{S}{S^2} + a^2$$ is
