two friends are talking to another person across the building the other person can hear them but not see them why is this?

11. you want to calculate the displacement of an object thrown over a bridge. using -10 m/s2 for acceleration due to gravity, what would be the total displacement of the object if it took 8 seconds before hitting the water?

Asatellite component is in the shape of a cube with 10cm edges, has an evenly distributed mass of 2 kg and one bolt hole at each of four corners. if the maximum predicted random vibration environment is 10 grms, what bolt size would be a good choice for restraint? what other factors might drive bolt size besides force/stress?

An electron is traveling with initial kinetic energy k in a uniform electric field. the electron comes to rest momentarily after traveling a distance d. (a) what is the magnitude of the electric field