An oscillator makes four vibrations in one second. what is its period and frequency

The most important difference between a wedge and an inclined plane is a. their size b. their shape c. how they are used d. what they are made of

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?

With physics question #5? for any !