# Fluids Questions and Answers

Physics

FluidsA sealed syringe of gas initially has a volume of 20 cm³. You press on the syringe until its volume is cut in half. a) What change was there in the pressure in the syringe? b) What assumptions did you make in arriving at your answer to part a)?

Physics

FluidsA piece of Styrofoam is floating in water. A piece of metal is placed on top of the Styrofoam. a) Does the depth of the Styrofoam in the water change? In what way? Explain. b) Does the Styrofoam displace more or less water when the piece of metal is on top of it? Explain.

Physics

FluidsA device for making sensitive pressure measurements is called a manometer. A manometer is a U-shaped tube filled with a liquid as shown. a) If the pressure at point A is lower than that at point B, how will the heights of the water on the two sides of the tube compare? Explain. b) If instead the pressure is higher at point A, how will the heights of the water on the two sides compare? Explain.

Physics

FluidsA completely submerged 0.41-kg ball is attached by a cable of negligible mass to the bottom of a tank of gasoline, as shown. The volume of the ball is 0.0075 m³ (Pgasoline
680 kg/m³),
(a) Find the mass of gasoline displaced by the ball,
(b) Find the magnitude of the buoyancy force of gasoline.
(c) Find the tension in the cable.

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 the aircraft travels at 58.0 m/s, so that the air speed relative to the bottom of the wing is 58.0 m/s. Given the sea level density of air to be 1.29 kg/m, how fast (in m/s) must it move over the upper surface to create the ideal lift?
(b) How fast (in m/s) must air move over the upper surface at a cruising speed of 240 m/s and at an altitude where air density is one-fourth that at sea level? (Note that this is not all of the aircraft's lift--some comes from the body of the plane, some from engine thrust, and so on. Furthermore, Bernout's principle gives an approximate answer because flow over the wing creates turbulence.)

Physics

Fluids1) A 10,000 N car is on a circular hydraulic press plate with radius 2 meters. A smaller plater with radius 0.4 meters is used for lifting the car. What is the force required?

Physics

FluidsWater is hard to compress as its bulk modulus is 2.0 x 10° pascals. If a volume of water is subjected to a pressure
increase of 150 pascals and its initial volume is 480 cubic meters,
(a) What will be the fractional decrease in the volume?
(b) What would be the change in volume?

Physics

FluidsJason takes off across level water on his jet-powered skis. The combined mass of Jason and his skis is 75 kg (the mass of the fuel is negligible). The skis produce a forward thrust of 200 N and have a coefficient of kinetic friction with water of 0.10. Unfortunately, the skis run out of fuel after only 90 s. What is Jason's top speed?
150 m/s
240 m/s
90 m/s
24 m/s

Physics

FluidsGiven a sphere of diameter 0.001 m and velocity = 30 m/s show whether quadratic or linear terms dominate the drag force present.
For (A) find the velocity at t = 2.0 seconds given that c1 = 10 and c2 = 4

Physics

FluidsA cannon tilted upward at θ = 25° fires a cannonball with a speed of 94 m/s.
Part A
At that instant, what is the component of the cannonball's velocity parallel to the ground?
Express your answer in meters per second.

Physics

FluidsA piston of surface area 1200 mm² moves inside a cylinder with a velocity of 6 m/s. The piston has a diameter of 50 mm and the cylinder has a diameter of 50.2 mm. The space between symmetrically positioned piston and cylinder is filled with lubricant of coefficient of viscosity 2.5 x 10^-2 Pa.s. What is the power loss (in watts)?

Physics

FluidsThe radius of a soap bubble is r. The surface tension solution T. Keeping soap temperature constant, the radius of the soap bubble is doubled, the energy necessary for this will be
(1) 24πr² T
(2) 8πr²T
(3) 12πr²T
(4) 16πr²T

Physics

FluidsTwo cylindrical vessels of equal cross sectional area A, contain liquid of density p, upto the heights h₁ and h2. After inter connection the levels become equal then work done by force of gravity in this process is:
A. ρA(h₁-h₂/2)²g
B. ρA(h₁-h₂/2)g
C. ρA(h₁+h₂/2)²g
D. ρA(h₁-h₂)g

Physics

FluidsA wind with speed 40 m/s blows parallel to the roof of a house. The area of the roof is 250m². Assuming that the pressure inside the house is atmospheric pressure, the force exerted by the wind on the roof and the direction of the fore will be:
(ρair = 1.2kg/m³)
A. 4.8 x 10⁵ N, upwards
B. 2.4 x 10⁵ N,upwards
C. 2.4 x 10⁵ N, downwards
D. 4.8 x 10⁵ N,downwards

Physics

FluidsTwo cylindrical vessel of equal cross-sectional area. A contain water upto height h₁ and h₂. The vessels are interconnected so that the levels in them become equal. The work done by the force of gravity during the process is
A. zero
B. ρA(h₁+h₂ /2)² 9
C. ρA(h₁-h₂ /2)² 9
D. ρAh₁ h₂/2 g

Physics

FluidsA glass plate of length 0.1m. breadth 15 x 10-³m and thickness 2 × 10-³ m weights 8 × 10-³ kg in air. It is heid vertically with its longer side horizontal and its lower half immersed in water. If the surface tension of water is 72 × 10-³ N/m the apparent weight of the plate will be
A. 97.4 x 10-³ N
B. 36.1 x 10-³ N
C. 72.2 × 10-³ N
D. 79.4 x 10-³ N

Physics

FluidsA 3-m long water pipe with the cross-sectional area 20 cm2 inclined at 30 degrees to the wall is connected to a system under the pressure P1 at the top end. The water flows here with the speed of v1. At the bottom end it is joined with a horizontal pipe of the cross-sectional area 5 cm2. The water flows out of the horizontal pipe at a speed of 10 m/s. Find
a) The rate of flow in L/s (1L-10^-3 m3, 1 m3 = 10^6 cm3)
b) The speed v1
c) The pressure P1

Physics

FluidsA boat, that has a density of 0.66 g/cm³, is 3m long, 1.5m wide, and 50cm high. When the boat is floating in water, how high is the dry surface of the boat?
a) 0.33 m
b) 0.5 m
c) 0.17 m
d) 0.83 m

Physics

FluidsA room measures 3.0 m by 4.5 m by 6.0 m. If the heating and air-conditioning ducts (one in and one out) to and from the room are circular with a diameter of 0.30 m, and all the air in the room is exchanged every 12 minutes:
i) What is the flow rate?
ii) What is the speed of the air in the ducts?
a) Q = 7.6 m³/min, V = 2.5 m/s
b) Q = 6.75 m³/min, V = 1.6 m/s
c) Q=67.5 m³/min, V = 1.8 m/s
d) Q = 6.75 cm³/min, V = 1.6 cm/s

Physics

FluidsA river narrows at a rapids from a width of 12 m to a width of only 5.8 m. The depth of the river before the rapids is 2.7 m; the depth in the rapids is 0.85 m. If the speed of the water before the rapids is 1.2 m/s, find the speed of the water in the rapids.
a) 6.5 m/s
b) 2.4 m/s
c) 7.9 m/s
d) 1.2 m/s

Physics

FluidsA solid ball of volume V is dropped in a viscous liquid. It experiences a viscous force F. If the solid ball of volume 2V of same material is dropped in the same fluid, then the viscous force acting on it will be
A. nF/2
B. F/2
C. 2F
D. 2nF

Physics

FluidsAn ocean-going research submarine has a 40.0 cm diameter window 8.90 cm thick. The manufacturer says the window can withstand forces up to 1.00×10^6 N. What is the submarine's maximum safe depth?
The pressure inside the submarine is maintained at 1.0 atm.