Sign in
12thPass logo
New chatPYQ LibraryDoubtsRank report
Sign in to see Recents

Your guest activity stays on this device

Sign in to save progress →
Sign in

Properties of Matter question

2015 · Q148
Guest · filters and generic practice availableBrowsing as a guest · PYQ filters and generic practice are available. Sign in only for personalised features and saved progress.
  1. PYQ Library
  2. /NEET
  3. /Physics
  4. /Properties of Matter
  5. /2015 · Q148

Properties of Matter question

2015 · Q148

NEETPhysicsProperties of MatterMCQ+4 / −1
A wind with speed 40 m/s blows parallel to the roof of a house. The area of the roof is 250 m2. Assuming that the pressure inside the house is atmospheric pressure, the force exerted by the wind on the roof and the direction of the force will be (ρair=1.2kg/m3)({\rho _{air}} = 1.2kg/{m^3})(ρair​=1.2kg/m3)
  1. A
    2.4 ×\times× 105 N, upwards
  2. B
    2.4 ×\times× 105 N, downwards
  3. C
    4.8 ×\times× 105 N, downwards
  4. D
    4.8 ×\times× 105 N, upwards
View written solutionFree

Correct answer: A

Using Bernoulli's theorem and assuming density constant,

P1+1/2ρv12 = P2+1/2ρv22

where:
P2 = pressure outside house
P1 = pressure inside house
v1 = speed of air inside house
v2 = speed of air outside house

Pressure difference,

P1 – P2 = 1/2ρ [v22 – v12]

Now, P1 – P2 = 1/2 × 1.2 [402 – 02]

P1 – P2 = 960 N/m2

Since Pressure P = Force/Area, so force acting on roof will be :

F = P × A

F = 960 × 250

F = 960 × 1000/4

F = 24×104 or 2.4×105 N

which is acting upward.

PreviousNext

More from Properties of Matter

  • On observing light from three different starts P, Q and R, it was found that intensity of violet colour is maximum in the spectrum of P, the intensity of green colour is maximum in the spectrum of R and the intensity of red colour is…2015 · MCQ
  • The approximate depth of an ocean is 2700 m. The compressiblity of water is 45.4 × 10−11 Pa−1 and density of water is 103 kg/m3. What fractional compression of water will be obtained at the bottom of the ocean?2015 · MCQ
  • Copper of fixed volume V is drawn into wire of length l. When this wire is subjected to a constant force F, the extension produced in the wire is Δl. Which of the following graphs is a straight line ?2014 · MCQ
  • A certain number of spherical drops of a liquid of radius r coalesce to form a single drop of radius R and volume V. If T is the surface tension of the liquid, then2014 · MCQ
  • Steam at 100oC is passed into 20 g of water at 10oC. When water acquires a temperature of 80oC, the mass of water present will be [Take specific heat of water = 1 cal g−1 oC−1 and latent heat of steam = 540 cal g−1]2014 · MCQ
  • Certain quantity of water cools from 70oC to 60oC in the first 5 minutes and to 54oC in the next 5 minutes. The temperature of the surroundings is2014 · MCQ
  • If the ratio of diameters, lengths and Young's modulus of steel and copper wires shown in the figure are p, q and s respectively, then the corresponding ratio of increase in their lengths would be Includes diagram2013 · MCQ
  • Two metal rods 1 and 2 of same lengths have same temperature difference between their ends. Their thermal conductivities are K1 and K2 and cross sectional areas A1 and A2, respectively. If the rate of heat conduction in 1 is four times…2013 · MCQ