Does an electromagnet wave require a medium? yes or no does a mechanical wave require a medium? yes or no *one is yes and one is no*

Automobile fuel efficiency is often measured in miles that the car can be driven per gallon of fuel (mpg). heavier cars tend to have lower fuel efficiencies (lower mpg ratings). which variable (weight or fuel efficiency) is most naturally considered the explanatory (predictor) variable in this context?

A17,250 kg rocket is pushed with a thrust of 6,450,284 n. what is the acceleration of the rocket?

This is the number of complete movements of a wave per second.