What is the magnitude of the maximum stress that exists at the tip of an internal crack having a radius of curvature of 2.5 × 10−4 mm and a crack length of 2.5 × 10−2 mm when a tensile stress of 170 MPa is applied (in MPa)

Density of salty water as compared to the density of pure water is(a) is less(b) is always equal(c) is always more(d) may be less or more

The ratio of lift to drag l/d for a wing or airfoil is an important aerodynamic parameter, indeed, it is a direct measure of the aerodynamic efficiency of the wing. if a wing is pitched through a range of angle of attack, l/d first increases, then goes through a maximum, and then decreases. consider an infinite wing with an naca 2412 airfoil. estimate the maximum value of l/d. assume that the reynolds number is 9x10^6.

Which bonds are found inside a water molecule