A child pushes his younger brother with 54 newtons of force, causing him to accelerate at 3.8 m/s/s. Assuming no friction, what is the mass of the younger brother? Answer to one decimal.

What is the thinnest soap film (excluding the case of zero thickness) that appears black when illuminated with light with a wavelength of 480 ? the index of refraction of the film is 1.34, and there is air on both sides of the film. express your answer in nanometers. hint 1. how to approach th