Sound waves require a medium to travel through, such as a solid, liquid or gas because a) waves cannot move through a vacuum b) sound only works within certain pressures c) waves only work within certain tempuratures d) sound is molecules bumping into one another

What is the energy of a photon of ultraviolet radiation with a frequency of 4.4 × 1015 hz? planck’s constant is 6.63 × 10–34

What is an electric motor? explain its operation. 2-3 sentence

An astronaut floating in space is trying to use her jetpack to get back to her space station, but she is being pulled away by a nearby planet, as shown in the image below. her jetpack provides a constant thrust of 310 n. if she angles her jetpack in such a way that it cancels out the vertical force due to the planet's gravity, what is her net horizontal force? thaud 487 o a. 54.8 n toward the space station o b. 212.9 n toward the space station o c. 185.2 n toward the space station o d 956 n toward the space station