Summary Fluid dpp

XI MED ‘A’
PHYSICS
Fluids DPP # 72 TIME : 35 Min

1. The speed of air flow on the upper and lower surfaces of a wing of an aeroplane are v1 and v2 respectively. If A
is the projectional area along horizontal of the wing and is the density of air, then the upward lift is
1 1 1 1
(1) A  v1  v 2  (2) A  v1  v 2  (3) A  v12  v 22  (4) A  v12  v 22 
2 2 2 2
2. Equal masses of water and a liquid of densities of 1 g/cm3 and 2 g/cm3 are mixed together. Then the mixture has
density of
2 4 3
(1) g / cm 3 (2) g / cm 3 (3) g / cm 3 (4) 3 g/cm3
3 3 2
3. The cylindrical tube of a spray pump has radius R. One end of it has n fine holes, each of radius r. If the speed of
liquid in the tube is v, the speed of the ejection of the liquid through the holes is

v2R vR 2 vR 2 vR 2
(1) (2) (3) (4)
nr n 2r2 nr 2 n 3r 2
4. During a stom, density of air is found to be and flow velocity v outside a mud hut whose root is covered with
an asbestos sheet of mass m and surface area A.




Find the condition for which the roof top blows up.

Av 2
(1) Av2  mg (2) 2Av2  mg (3)  mg (4) Av2  2mg
4
5. To get the maximum flight, a ball must be thrown as
(1) (2) (3) (4) Any of (1), (2), (3)
6. A cylindrical vessel of height h and base area S is filled with water. An office of area A << S is opened in the
bottom of the vessel. Neglecting the viscosity of water determine how soon all the water will flow out of the
vessel?

S 2h A g 2h S
(1) (2) (3) SA 2gh (4)
A g S 2h g A

H
7. The height of water level in tank is H. The range of water stream coming out of a hole at depth from upper
4
water level will be

3H 2H H
(1) (2) (3) (4) 3H
2 3 2



PERFECT EDUCATION, 17-18, Vinayak vihar pharmacy road, Sri Ganganagar -335001 Mob. 84321-00020, 7821822364 (1)