When henrietta leavitt discovered the period-luminosity relationship, she used cepheid stars that were all located in the small magellanic cloud. why did she need to use stars in another galaxy and not cepheids located in the milky way?

According to the phase diagram for water, how is the state of water determined? proceed up a vertical line at any given temperature read the phase at the intersection of any given temperature and pressure at a given pressure, proceed horizontally to the s-l or l-g line

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

An object dropped from cliff falls with a constant acceleration of 10 metre per second square find its speed of two seconds after it was dropped