Fluid Statics and Dynamics MCQs

Question 1

A spinning cricket ball swings (curves) because:

Accepted Answer

air flows at different speeds on the two sides, creating a pressure difference

Answer

gravity acts sideways

Answer

it gets lighter

Answer

the bowler's hand pushes it

Question 2

The Bernoulli effect states that where the speed of a fluid is higher:

Accepted Answer

its pressure is lower

Answer

its pressure is higher

Answer

its temperature is higher

Answer

its density is higher

Question 3

Viscous drag forces are:

Accepted Answer

non-conservative — they convert kinetic energy into heat

Answer

always zero

Answer

conservative

Answer

attractive forces

Question 4

Water flows at 2 m/s through a pipe at pressure 1.5 10^5 Pa. The pipe rises 5 m with no change in area. The pressure at the top is (rho = 1000 kg/m^3, g = 9.8):

Accepted Answer

1.01 10^5 Pa

Answer

1.48 10^5 Pa

Answer

1.99 10^5 Pa

Answer

1.5 10^5 Pa

Question 5

In the Venturi meter above (water, 1000 kg/m^3), the pressure difference between wide part and throat is:

Accepted Answer

1.2 10^4 Pa

Answer

4 10^3 Pa

Answer

1.25 10^4 Pa

Answer

2.4 10^4 Pa

Question 6

Motor oil is chosen with suitable viscosity so that:

Accepted Answer

it flows when cold and still lubricates when hot

Answer

it becomes a solid

Answer

it boils easily

Answer

it never flows

Question 7

If mass were not conserved in a pipe, the equation of continuity would:

Accepted Answer

not hold

Answer

give zero speed

Answer

still hold

Answer

become Bernoulli's equation

Question 8

Blowing between two hanging sheets of paper makes them:

Accepted Answer

move together

Answer

move apart

Answer

stay still

Answer

burn

Question 9

Which device does NOT rely on the Bernoulli effect?

Accepted Answer

a hydraulic jack

Answer

a Venturi meter

Answer

an atomiser

Answer

an aircraft wing

Question 10

A block of density 900 kg/m^3 floats in a liquid of density 1030 kg/m^3. The fraction of its volume below the surface is:

Accepted Answer

0.874

Answer

1.14

Answer

0.437

Answer

0.126

Question 11

A Venturi meter has wide area 10 cm^2 and throat 2 cm^2. If water enters at 1 m/s, its speed at the throat is:

Accepted Answer

5 m/s

Answer

25 m/s

Answer

1 m/s

Answer

0.2 m/s

Question 12

Blowing over the top of a strip of paper held below the lips makes the paper:

Accepted Answer

rise

Answer

stay still

Answer

fall

Answer

tear

Question 13

In a pipe, a viscous liquid flows fastest:

Accepted Answer

along the centre

Answer

at the walls

Answer

uniformly everywhere

Answer

nowhere

Question 14

The drag force on a body moving through a fluid acts:

Accepted Answer

opposite to the body's velocity

Answer

perpendicular to motion

Answer

in the direction of motion

Answer

upward always

Question 15

Turbulent flow is characterised by:

Accepted Answer

irregular, swirling motion with eddies

Answer

smooth parallel layers

Answer

zero velocity

Answer

constant velocity everywhere

Question 16

Water moves at 0.5 m/s in a pipe of diameter 3 cm, which narrows to 1 cm. The speed in the narrow part is:

Accepted Answer

4.5 m/s

Answer

1.5 m/s

Answer

2.25 m/s

Answer

9 m/s

Question 17

Water flows through a hose of area 3 cm^2 and fills a 15 litre bucket in 50 s. The speed of the water in the hose is:

Accepted Answer

1 m/s

Answer

10 m/s

Answer

0.1 m/s

Answer

0.3 m/s

Question 18

A body of volume 0.002 m^3 is fully immersed in a liquid of density 1000 kg/m^3. The upthrust on it is (g = 9.8):

Accepted Answer

19.6 N

Answer

1.96 N

Answer

196 N

Answer

39.2 N

Question 19

The Magnus effect explains:

Accepted Answer

the curved path of a spinning ball

Answer

elastic collisions

Answer

flotation of ships

Answer

terminal velocity

Question 20

Using Stokes' law, the drag on a sphere of radius 1 10^-5 m moving at 0.01 m/s through a fluid of viscosity 1.8 10^-5 Pa s is:

Accepted Answer

3.39 10^-11 N

Answer

6.79 10^-11 N

Answer

1.8 10^-12 N

Answer

1.7 10^-11 N

Question 21

A river 20 m wide and 2 m deep flows at 1 m/s. The mass of water passing per second (density 1000 kg/m^3) is:

Accepted Answer

4 10^4 kg/s

Answer

40 kg/s

Answer

2 10^4 kg/s

Answer

4 10^3 kg/s

Question 22

A shower curtain moves inward when the shower is on because:

Accepted Answer

the moving air and water inside lower the pressure

Answer

the room air is lighter

Answer

the water pushes it inward

Answer

it is attracted by static

Question 23

A ball in a fast stream of water from a tap is pulled into the stream. This is because:

Accepted Answer

the fast water has lower pressure than the still air around

Answer

the ball becomes lighter

Answer

gravity reverses

Answer

water is sticky only

Question 24

Superfluid helium is used to cool:

Accepted Answer

superconducting magnets and sensitive detectors

Answer

car engines

Answer

drinks

Answer

houses

Question 25

Backspin on a golf ball gives it:

Accepted Answer

lift, so it travels further

Answer

a downward force

Answer

less range

Answer

more weight

Fluid Statics and Dynamics MCQs — Physics (page 7)

151. A spinning cricket ball swings (curves) because:

152. The Bernoulli effect states that where the speed of a fluid is higher:

153. Viscous drag forces are:

154. Water flows at 2 m/s through a pipe at pressure 1.5 10^5 Pa. The pipe rises 5 m with no change in area. The pressure at the top is (rho = 1000 kg/m^3, g = 9.8):

155. In the Venturi meter above (water, 1000 kg/m^3), the pressure difference between wide part and throat is:

156. Motor oil is chosen with suitable viscosity so that:

157. If mass were not conserved in a pipe, the equation of continuity would:

158. Blowing between two hanging sheets of paper makes them:

159. Which device does NOT rely on the Bernoulli effect?

160. A block of density 900 kg/m^3 floats in a liquid of density 1030 kg/m^3. The fraction of its volume below the surface is:

161. A Venturi meter has wide area 10 cm^2 and throat 2 cm^2. If water enters at 1 m/s, its speed at the throat is:

162. Blowing over the top of a strip of paper held below the lips makes the paper:

163. In a pipe, a viscous liquid flows fastest:

164. The drag force on a body moving through a fluid acts:

165. Turbulent flow is characterised by:

166. Water moves at 0.5 m/s in a pipe of diameter 3 cm, which narrows to 1 cm. The speed in the narrow part is:

167. Water flows through a hose of area 3 cm^2 and fills a 15 litre bucket in 50 s. The speed of the water in the hose is:

168. A body of volume 0.002 m^3 is fully immersed in a liquid of density 1000 kg/m^3. The upthrust on it is (g = 9.8):

169. The Magnus effect explains:

170. Using Stokes' law, the drag on a sphere of radius 1 10^-5 m moving at 0.01 m/s through a fluid of viscosity 1.8 10^-5 Pa s is:

171. A river 20 m wide and 2 m deep flows at 1 m/s. The mass of water passing per second (density 1000 kg/m^3) is:

172. A shower curtain moves inward when the shower is on because:

173. A ball in a fast stream of water from a tap is pulled into the stream. This is because:

174. Superfluid helium is used to cool:

175. Backspin on a golf ball gives it:

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