ISRO SC/ENG 2013

1) A small plastic boat loaded with pieces of steel roads is floating in a bath tub. If the cargo is dumped into the water, allowing the boat to float empty, the water level in the tub will

A. Rise
B. Fall
C. Remains thee same
D. Rise an then fall

2) Viscosity of water in comparison to mercury is

A. Higher
B. Lower
C. same
D. Unpredictable

3) Froude number is significant in

A. Supersonics, as with projectile and jet propulsion
B. Full immersion or completely enclosed flow, as with pipes, air craft wings, nozzles, etc
C. Simultaneous motion through two fluids where there is a surface discontinuity, gravity forces and wave making effect, as with ship’s hulls
D. All of these

4) The purpose of surge tank in a pipe line is to

A. Smoothen the flow of water
B. Minimize friction losses in pipe
C. Prevent occurrence of hydraulic jump
D. Relieve pressure due to water hammer

5) Head loss in turbulent flow in a pipe

A. Varies directly as velocity
B. Varies inversely as square of velocity
C. Varies approximately as square of velocity
D. Varies inversely as velocity

6) A tank 1.5 m stands on a trolley and is full of water. It has an orifice of diameter 0.1m at 0.3m from the bottom of the tank. If the orifice is suddenly opened and coefficient of discharge of the orifice is 0.60, then propelling force on the trolley will be

A. 69.37 N
B. 67.39 N
C. 63.79 N
D. 65.39 N

7) Consider steady, incompressible and irrotational flow through a reducer in a horizontal pipe, where the diameter is reduced from 20cm to 10 cm. The pressure in the 29 cm pipe just upstream of the reducer is 150 kPa. The fluid has a vapour pressure of 50 kPa and a specific weight of 5 Kn/m3. Neglecting frictional effects, the maximum discharge ( in m3/sec) that can pass through the reducer without causing cavitations is

A. 0.05
B. 0.16
C. 0.27
D. 0.38

8) For the stability of a floating body, under the influence of gravity alone, which of the following is true?

A. Metacentre should be below the center of gravity
B. Metacentre should be above the center of gravity
C. Metacenter and center of gravity must lie on the same horizontal line
D. Metacenter and center of gravity must lie on the same vertical line

9) A smooth pipe of diameter 200 mm carries water. The pressure in the pipe at section S1 (elecation:10m) is 50 kpa. At section S2(elevation : 12 m) the pressure is 20 kPa and velocity is 2 m/sec. Density of water is 1000 kg/m3 and acceleration due to gravity is 9.8 m/sec2. Which of the following is true?

A. Flow is from S1 to S2 and head loss is 0.53m
B. Flow is from S2 to S1, and head loss is 0.53 m
C. Flow is from S1 to S2 and head loss is 1.06 m
D. Flow is from S2 to S1 and head loss is 1.06m

10) The 2-D flow with velocity v =( x + 2y + 2) i + ( 4 – y ) j is

A. Compressible and irrotational
B. Compressible and not irrotational
C. Incompressible and irrotational
D. Incompressible and not irrotational

11) A venturimeter of 20 mm throat diameter is used to measure the velocity of water in a horizontal pipe of 40 mm diameter. If the pressure difference between the pipe and throat sections is found to be 30 kPa, then neglecting frictional losses, the flow velocity is

A. 0.2 m/sec
B. 1.0 m/sec
C. 1.4 m/secc
D. 2.0 m/sec

12) A model of a hydraulic turbine is tested at a head of 1/4th of that under which the full scale turbine works. The diameter of the model is half of that of thee full scale turbine. If N is the RPM of the full scale turbine, then RPM of the model will be

A. N/4
B. N/2
C. N
D. 2N





Get complete solution for all previous ISRO SC MECHANICAL papers.
Visit: www.keytoisro.com