151. The total pressure force on a plane area is equal to the area multiplied by the intensity of pressure at the centriod, if
(a) the area is horizontal
(b) the area is vertical
(c) the area is inclined
(d) all of the above
(e) none of the above.
Ans: d
152. A square surface 3 m x 3 m lies in a vertical line in water pipe its upper edge at vater surface. The hydrostatic force on square surface is
(a) 9,000 kg
(b) 13,500 kg
(c) 18,000 kg
(d) 27,000 kg
(e) 30,000 kg
Ans: b
153. The df pth of the centre of pressure on a vertical rectangular gate 8 m wide and 6 m high, when the water surface coincides with the top of the gate, is
(a) 2.4 m
(b) 3.0 m
(c) 4.0 m
(d) 2.5 m
(e) 5.0 m
Ans: b
154. If the atmospheric pressure on the surface of an oil tank (sp. gr. 0.8) is 0.2 kg/cm”, the pressure at a depth of 50 m below the oil surface will be
(a) 2 metres of water column
(b) 3 metres of water column
(c) 5 metres of water column
(d) 6 metres of water Column
(e) 7 metres of water column.
Ans: d
155. Metacentre is the point of intersection of
(a) vertical upward force through e.g. of body and centre line of body
(b) buoyant force and the centre line of body
(c) mid point between e.g. and centre of buoyancy
(d) all of the above
(e) none of the above.
Ans: b
156. Choose the wrong statement
(a) The horizontal component of the hydro-static force on any surface is equal to the normal force on the vertical projection of the surface
(b) The horizontal component acts through the centre of pressure for the vertical projection
(c) The vertical component of the hydrostatic force on any surface is equal to the weight of the volume of the liquid above the area
(d) he vertical component passes through the centre of pressure of the volume
(e) Centre of pressure acts at a greater depth than centre of gravity.
Ans: d
157. For a body floating in a liquid the normal pressure exerted by the liquid acts at
(a) bottom surface of the body
(b) e.g. of the body
(c) metacentre
(d) all points on the surface of the body
(e) all of the above.
Ans: d
158. Choose the wrong statement
(a) any weight, floating or immersed in a liquid, is acted upon by a buoyant force
(p) Buoyant force is equal to the weight of the liquid displaced
(c) The point through which buoyant force acts, is called the centre of buoyancy
(d) Centre of buoyancy is located above the centre of gravity of the displaced liquid
(e) Relative density of liquids can be determined by means of the depth of flotation of hydrometer.
Ans: d
159. According to the principle of buoyancy a body totally or partially immersed in a fluid will be lifted up by a force equal to
(a) the weight of the body
(b) more than the weight of the body
(c) less than the weight of the body
(d) weight of the fluid displaced by the body
(e) weight of body plus the weight of the fluid displaced by the body.
Ans: d
160. When a body floating in a liquid, is displaced slightly, it oscillates about
(a) e.g. of body
(b) centre of pressure
(c) centre of buoyancy
(d) metacentre
(e) liquid surface.
Ans: d
161. Buoyant force is
(a) resultant force acting on a floating body
(b) equal to the volume of liquid displaced
(c) force necessary to keep a body in equilibrium
(d) the resultant force on a body due to the fluid surrounding it
(e) none of the above.
Ans: d
l62. Ratio of inertia force to surface Jension is known as
(a) Mach number
(b) Froude number
(c) Reynold’s number
(d) Weber’s number
(e) none of the above.
Ans: d
163. A ship whose hull length is 100 m is to travel at 10 m/sec. For dynamic similarity, at what velocity should a 1:25 model be towed through water ?
(a) 10 m/sec
(b) 25 m/sec
(c) 2 m/sec
(d) 50 m/sec
(e) 250 m/sec
Ans: c
164. A model of a reservior is drained in 4 mts by opening the sluice gate. The model scale is 1: 225. How long should it take to empty the prototype ?
(a) 900 minutes
(b) 4 minutes
(c) 4 x (225)3/2 minutes
(d) 4 (225)1/3 minutes
(e) 4 x V225 minutes
Ans: e
165. A model of torpedo is tested in a towing tank at a velocity of 25 m/sec. The prototype is expected to attain a velocity of 5 m/sec. What model scale has been used ?
(a) 1 : 5
(b) 1 : 2.5
(c) 1 :25
(d) 1:V5
(e) 1 : 53/2
Ans: a
166. Ratio of inertia force to elastic force is known as
(a) Mach number
(b) Froude number
(c) Reynold’s number
(d) Weber’s number
(e) none of the above.
Ans: a
167. For a floating body to be in stable equilibrium, its metacentre should be
(a) below the centre of gravity
(b) below the centre of buoyancy
(c) above the centre of buoyancy
(d) between e.g. and centre of pressure
(e) above the centre of gravity.
Ans: e
168. For a floating body to be in equilibrium
(a) meta centre should be above e.g.
(b) centre of buoyancy and e.g. must lie on same vertical plane
(c) a righting couple should be formed
(d) all of the above
(e) none of the above.
Ans: d
169. The two important forces for a floating body are
(a) buoyancy, gravity
(b) buoyancy, pressure
(c) buoyancy, inertial
(d) inertial, gravity
(e) gravity, pressure.
Ans: a
170. Choose the wrong statement
(a) The centre of buoyancy is located at the centre of gravity of the displaced liquid
(b) For stability of a submerged body, the centre of gravity of body must lie directly below the centre of buoyancy
(c) If e.g. and centre of buoyancy coin¬cide, the submerged body must lie at neutral equilibrium for all positions
(d) For stability of floating cylinders or spheres, the e.g. of body must lie below the centre of buoyancy
(e) All floating bodies are stable.
Ans: e
171. Centre of pressure on an inclined plane is
(a) at the centroid
(b) above the centroid
(c) below the centroid
(d) at metacentre
(e) at centre of pressure.
Ans: c
172. An open vessel of water is accelerated up an inclined plane. The free water surface will
(a) be horizontal
(b) make an angle in direction of inclina¬tion of inclined plane
(c) make an angle in opposite direction to inclination of inclined plane
(d) any one of above is possible
(e) none of the above.
Ans: c
173. The line of action of the buoyant force acts through the centroid of the
(a) submerged body
(b) volume of the floating body
(c) volume of the fluid vertically above the body
(d) displaced volume of the fluid
(e) none of the above.
Ans: d
174. Resultant pressure of the liquid in the case of an immersed body acts through
(a) centre of gravity
(b) centre of pressure
(c) metacentre
(d) centre of buoyancy
(e) in between e.g. and centre of pressure.
Ans: b
175. The centre of gravity of the volume of the liquid displaced by an immersed body is called
(a) centre of gravity
(b) centre of pressure
(c) metacentre
(d) centre of buoyancy
(e) centroid.
Ans: d
176. Differential monometer is used to measure
(a) pressure in pipes, channels etc.
(b) atmospheric pressure
(c) very low pressure
(d) difference of pressure between two points
(e) velocity in pipes
Ans: d
177. The pressure in the air space above an oil (sp. gr. 0.8) surface in a tank is 0.1 kg/cm. The pressure at 2.5 m below the oil surface will be
(a) 2 metres of water column
(b) 3 metres of water column
(c) 3.5 metres of water column
(d) 4 m of water column
(e) none of the above.
Ans: b
178. The time oscillation of a floating body with increase in metacentric height will be
(a) same
(b) higher
(c) lower
(d) lower/higher depending on weight of body
(e) unpredictable.
Ans: c
179. In an immersed body, centre of pressure is
(a) at the centre of gravity
(b) above the centre of gravity
(c) below be centre of gravity
(d) could be above or below e.g. depend¬ing on density of body and liquid
(e) unpredictable.
Ans: c
180. The normal stress is same in all directions at a point in a fluid
(a) only when the fluid is frictionless
(b) only when the fluid is incompressible and has zero viscosity
(c) when there is no motion of one fluid layer relative to an adjacent layer
(d) irrespective of the motion of one fluid layer relative to an adjacent layer
(e) in case of an ideal fluid.
Ans: c
181. Select the correct statement
(a) Local atmospheric pressure depends upon elevation of locality only
(b) Standard atmospheric pressure is the mean local atmospheric pressure a* sea level
(c) Local atmospheric pressure is always below standard atmospheric pressure
(d) A barometer reads the difference be-tween local and standard atmospheric pressure
(e) Gauge pressure is equal to atmospheric pressure plus instrument reading.
Ans: b
184. For measuring flow by a venturimeter, if should be installed in
(a) vertical line
(b) horizontal line
(c) inclined line with flow downward
(d) inclined line with upward flow
(e) in any direction and in any location.
Ans: e
185. Total pressure on a lmxlm gate immersed vertically at a depth of 2 m below the free water surface will be
(a) 1000 kg
(b) 4000 kg
(c) 2000 kg
(d) 8000 kg
(e) 16000 kg
Ans: a
186. Hot wire anemometer is used to measure
(a) pressure in gases
(b) liquid discharge
(c) pressure in liquids
(d) gas velocities
(e) temperature.
Ans: d
187. Rotameter is a device used to measure
(a) absolute pressure
(b) velocity of fluid
(c) flow
(d) rotation
(e) velocity of air.
Ans: c
188. Flow of water in a pipe about 3 metres in diameter can be measured by
(a) orifice plate
(b) venturi
(c) rotameter
(d) pitot tube
(e) nozzle
Ans: d
189. True one-dimensional flow occurs when
(a) the direction and magnitude of the veiocity at all points are identical
(b) the velocity of successive fluid par-ticles, at any point, is the same at suc-cessive periods of time
(c) the magnitude and direction of the velocity do not change from point to point in the fluid
(d) the fluid particles move in plane or parallel planes and the streamline patterns are identical in each plane
(e) velocity, depth, pressure etc. change from point to point in the fluid flow.
Ans: a
190. An ideal flow of any fluid must satisfy
(a) Pascal law
(b) Newton’s law of viscosity
(c) boundary layer theory
(d) continuity equation
(e) Bernoulli’s theorem.
Ans: d
191. In the case of steady flow of a fluid, the acceleration of any fluid particle is
(a) constant
(b) variable
(c) zero
(d) zero under limiting conditions
(e) never zero.
Ans: c
193. Non uniform flow occurs when
(a) the direction and magnitude of the velocity at all points are identical
(b) the velocity of successive fluid particles, at any point, is the same at successive periods of time
(c) the magnitude aricf direction of the velocity do not change from point to point in the fluid
(d) the fluid particles move in plane or parallel planes and the streamline patterns are identical in each plane
(e) velocity, depth, pressure, etc. change from point to point in the fluid flow.
Ans: e
194. During the opening of a valve in a pipe line, the flow is
(a) steady
(b) unsteady
(c) uniform
(d) laminar
(e) free vortex type.
Ans: b
195. Uniform flow occurs when
(a) the flow is steady
(b) the flow is streamline
(c) size and shape of the cross section in a particular length remain constant
(d) size and cross section change uniformly along length
(e) flow occurs at constant fate.
Ans: c
196. Gradually varied flow is
(a) steady uniform
(b) non-steady non-uniform
(c) non-steady uniform
(d) steady non-uniform
(e) true one-dimensional.
Ans: d
197. Steady flow occurs when
(a) the direction and magnitude of the velocity at all points are identical
(b) the velocity of successive fluid par-ticles, at any point, is the same at successive periods of time
(c) the magnitude and direction of the velocity do not change from point to point in the fluid
(d) the fluid particles move in plane or parallel planes and the streamline patterns are identical in each plane
(e) velocity, depth, pressure, etc. change from point to point in the fluid flow.
Ans: b
198. The flow which neglects changes in a transverse direction is known as
(a) one dimensional flow
(b) uniform flow
(c) steady flow
(d) turbulent flow
(e) streamline flow.
Ans: a
199. The flow in which each liquid particle has a definite path and their paths do not cross each other is called
(a) one dimensional flow
(b) uniform flow
(c) steady flow
(d) turbulent flow
(e) streamline flow.
Ans: e
200. The flow in which conditions do not change with time at any point, is known as
(a) one dimensional flow
(b) uniform flow
(c) steady flow
(d) turbulent flow
(e) streamline flow.
Ans: c