# Fluids Questions and Answers

Physics

FluidsWater is moving at through a horizontal hose at a a velocity of 2 m/sec. The radius of the hose is 0.08 m. What is the volume flow rate of the water?
0.04 m³/sec
0.4 m³/sec
4.0 m³/sec.
40.0 m³/sec

Physics

FluidsWater is moving at through a horizontal hose. The radius of the hose changes. When the radius of the hose is 0.08 m, the speed of the water is 2 m/sec. What is the radius of the hose when the speed of the water is 15 m/sec?
A. 0.03 m
B. 0.3 m
C. 3.0 m
D. 30.0 m

Physics

FluidsAtmospheric pressure is about 1.01 x 105 Pa. How large a force does the atmosphere exert on a 4 cm² on the top of your head?

Physics

FluidsWhen you place an egg in water, it sinks. If you add salt to the water, after some time the egg floats. Choose the correct explanation.
Adding salt to the water increases its volume. When the volume of the water matches that of the egg, the egg becomes neutrally buoyant and floats.
Adding salt to the water decreases its density. When the density of the water matches that of the egg, the egg becomes neutrally buoyant and floats.
Adding salt to the water decreases its volume. When the volume of the water matches that of the egg, the egg becomes neutrally buoyant and floats.
Adding salt to the water increases its density. When the density of the water matches that of the egg, the egg becomes neutrally buoyant and floats.

Physics

FluidsA rock with a mass of 540 g in air is found to have an apparent mass of 342 g when submerged in water. (a) What mass of water is displaced? (b) What is the volume of the rock? (c) What is its average density? Is this consistent with the value for granite? (granite has a density of 2700 kg/m³)

Physics

FluidsA 30-cm-diameter vertical cylinder is sealed at the top by a frictionless 16 kg piston. The piston is 76 cm above the bottom when the gas temperature is 306°C. The air above the piston is at 1.00 atm pressure.
What is the gas pressure inside the cylinder? Express your answer with the appropriate units.
What will the height of the piston be if the temperature is lowered to 19°C? Express your answer with the appropriate units.

Physics

FluidsA frequently quoted rule of thumb in aircraft design is that wings should produce about 1000 N of lift per square meter of wing. (The fact that a wing has a top and bottom
surface does not double its area.) (a) At takeoff, an aircraft travels at 58.1 m/s, which is the airspeed just below the wing. Given the sea level density of air to be 1.29 kg/m³, how
fast must it move in m/s over the upper surface to create the ideal lift?
Type your answer...

Physics

FluidsA major artery with a cross-sectional area of 1.02 cm2 branches into 18 smaller arteries, each with an average cross-sectional area of 0.306 cm². By what factor (<1) is the average velocity of the blood reduced when it passes into these branches?
0.19

Physics

FluidsA wooden block is floating on water kept in beaker. 40% of the block is above the water surface. Now
the beaker is kept inside a lift that starts going upward with acceleration equal to g/2. The block will then
A sink
B float with 10% above the water surface
C float with 40% above the water surface
D float with 70% above the water surface

Physics

FluidsA small metal sphere of radius a is falling with a
velocity v through a vertical column of a viscous
liquid. If the coefficient of viscosity of the liquid is
n, then the sphere encounters an opposing force
of:
A 6πnа² v
B 6nv/πa
C 6πnav
D πnv/6a3

Physics

FluidsA beaker with a liquid of density 1.4gcm3 is in balance over one pan of a weighing machine. If a solid of mass 10g and density 8gcm-3 is now hung from the top of that pan with a thread and sinking fully in the liquid without touching the bottom, the extra weight to be put on the other pan for balance will be

Physics

FluidsA spherical particle falling at a terminal speed in a liquid must have the gravitational force balanced by the drag force and the buoyant
force. The buoyant force is equal to the weight of the displaced fluid, while the drag force is assumed to be given by Stokes Law:
Fd=6xRny.
where R is the radius of the object, 7 is the coefficient of viscosity in the fluid, and v is the terminal speed.
50% Part (a) Give the equation for terminal speed in the variables from Stokes law, and the densities of the sphere p, and the fluid pj.

Physics

FluidsSuppose there is a 0.45 mm thick layer of 20°C water between two microscope slides. The area of overlap between the two slides is 7.2 cm²
What magnitude of force is needed to pull one microscope slide over the other at a speed of 0.85 cm/s? Take the viscosity of water at 20° C as 1.002

Physics

Fluids(10 points total) Tim's PhD experiment, the Sudbury Neutrino Observatory, used a 1.0 x 106 kg container of heavy water, which has a density of 1110 kg/m³, submerged in normal water (density 1000 kg/m³). Ropes were used to support the container of heavy water.
A. (5 points) Draw a free-body diagram for the container of heavy water in the box at right. Be sure the forces are clearly labeled.
B. (5 points) Calculate the force required of the ropes to keep the heavy water in equilibrium.

Physics

FluidsA sump pump (used to drain water from the basement of houses built below the water table) is draining a flooded basement at the rate of 0.65 L/s, with an output pressure of 1.8 x 10³ Pa.

Physics

FluidsWater emerges from a faucet at a speed of 0.1 m/s. After falling a short distance, its speed increases to 0.9 m/s as a result of gravitational acceleration.
By what number would you multiply the original cross sectional area of the stream to find the area at the lower position?