What causes the increase in pitch as an ambulance siren moves toward you? the sound waves become compressed. the amplitude of the sound waves changes. the sound waves spread farther apart. the speed of the sound waves changes?

Calculate the amount of heat produced when 18000 coulombs of charge is transferred in one hour through a potential difference of 50v

Infrared rays have a shorter wavelength than question 11 options: x-rays. ultraviolet rays. radio waves. gamma rays.

Cathy is pedaling down a steep hill on her bicycle and wants to be able to coast up the next hill, which is 25 meters high, without pedaling. cathy and her bicycle have a mass of 75 kg. assuming her bicycle is 100% efficient, what would her speed have to be?