5) On a 120 km track, a train travels the first 30 Km at a uniform speed of 30 Km/h How fast must the train travel the next 90 Km so as to average 60 Km/h for the
entire trip

Wavelength,frequency,and energy are related.what happens to a wave as it’s wavelength gets shorter?

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

Atank has a shape of a cone with a radius at the top of 2 m and a height of 5 m. the tank also has a 1 m spout at the top of the tank. the tank is filled with water up to a height of 2 m. find the work needed to pump all the water out the top of the spout. (use 9.8 m/s2 for g and the fact that the density of water is 1000 kg/m3.)