PLZZZ HELP!! Which two options are reasons that electromagnetic waves can be used effectively in communication devices?

A. The speed at which they carry information can be varied

B. They require no wires to carry information

C. Any type of electromagnetic wave can be used for communication

D. They can travel through either air or other types of matter

Select the word from the list that best fits the definition classification of most stars on the h-r diagram

Heterogeneous mixture with larger particles that never settle is

The great sandini is a 60.0-kg circus performer who is shot from a cannon (actually a spring gun). you don’t find many men of his caliber, so you him design a new gun. this new gun has a very large spring with a very small mass and a force constant of 1100 n/m that he will compress with a force of 4400 n. the inside of the gun barrel is coated with teflon, so the average friction force will be only 40.0 n during the 4.00 m he moves in the barrel. at what speed will he emerge from the end of the barrel, 2.50 m above his initial rest position?