You come across a mysterious pond of an unknown liquid during your normal work day (lucky you). being curious, you submerge an upright large stick into the liquid. you note that 1.5 m of the stick is submerged. although you are holding the stick out 21 cm in front of you, the bottom of the stick appears 31 cm away. what is the mysterious liquid’s index of refraction?

Three point charges, two positive and one negative, each having a magnitude of 20 μc are placed at the vertices of an equilateral triangle (30 cm on a side). what is the magnitude of the electrostatic force on the negative charge

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.

It is really hard for me right know