You drop a rock in a pond and observe a wave propagating on the surface of the pond. how can you estimate the frequency, speed, and wavelength of the wave?

Explained

Explanation:

When we drop a rock in the pond, it creates a variety of wavelength in it. Among the the most dominant are waves due to surface tension and waves due to gravity. Because of the combined effect of both gravity and surface tension, there is critical wavelength that travel the most slowly than any other wave. The critical wavelength is about 1.7 cm for the water in lake on earth. So, looking at the ripples or the expanding circles we can say that their wavelength would be 1.7 cm.  

sleep paralysis is a parasomnia, events associated with sleep.

sleep paralysis happens when you are in the middle of waking up or falling asleep. it is the feeling of being conscious but unable to move. it definitely involves hallucinations.

i had a friend that had sleep paralysis and he told me a story one time where he was laying in bed and he couldn't move his body no matter how hard he tried and there was someone standing in the corner of his room coming towards him. he couldn't move and you can't "wake up" because you are already conscious. sometimes sleep paralysis can be triggered by frequent waking up during the night based off of multiple trips to the bathroom, or if you had ever been abused, sleep paralysis can start happening from things like that.