a boy runs from his house to school at speed 5m/s on a straight road and returns with speed of 10m/s. The distance between the house and school is 100m. Find his average velocity with explaination please

With i really need the correct answer!

The experiment was repeated many years later but the gases were mixed in a different type of container. a white solid was obtained which was xenon fluoride. predict whether you think 1) krypton and 2) radon will react with fluorine. explain reasons for your predictions

Abookcase has a mass of 38 kg and the coefficient of friction between it and the floor is 0.82 what is the maximum force of friction between the bookcase and the floor a 372n b 305n c 412n d 449n