An apple in a tree has a mass of 0.21 kg. If it is 7.2 meters above the ground, how much potential energy does it have?

According to an observer on earth, planet x is stationary. maria and samir depart earth on their spaceships at the same time, each flying at 0.5c. maria flies toward planet x and samir flies in the opposite direction. according to maria, her voyage to planet x takes 9 years. how many years does maria's voyage take according to samir?

As microwave light travels through a liquid, it moves at a speed of 2.2 x 108 m/s. if the frequency of this light wave is 1.1 x 108 hz, what is the wavelength of this microwave?

According to the image below, which season is about to begin in the southern hemisphere? a. summer b. autumn c. winter d. spring