Classes
Class 9Class 10First YearSecond Year
$A person is standing near a fast moving train. Is there any danger that he will fall towards it?$  $Explain how the swing is produced in a fast moving cricket ball.$  $For which position will the maximum blood pressure in the body have the smallest value. (a) Standing up right (b) Sitting (c) Lying horizontally (d) Standing on ones head?$  $What gauge pressure is required in the city mains for a stream flow a fire hose connected to the city mains to reach a vertical height of 15 \mathrm{~m} ?$  $Explain the difference between laminar flow and turbulent flow.$  $An airplane wing is designed so that when the speed of the air across the top of the wing is 450 \mathrm{ms}^{-1} the speed of air below the wing is 410 \mathrm{~ms}^{-1} . What is the pressure difference between the top and bottom of the wings? (Density of air =1.29 \mathrm{kgm}^{-3} ).$  $The radius of the aorta is about 1.0 \mathrm{~cm} and the blood flowing through it has a speed of about 30 \mathrm{cms}^{-1} . Calculate the average speed of the blood in the capillaries using the fact that although each capillary has a diameter of about 8 \times 10^{-4} \mathrm{~cm} there are literally millions of them so that their total cross section is about 2000 \mathrm{~cm}^{2} .$  