What is the speed of a wave if the wavelength is 200 m and the period is 20 s?

Wavelength is the distance between 2 crests or 2 troughs in a wave.

Period is the time taken for one wave to be completed. Frequency is the number of waves to pass a particular point in 1 second.

Period and frequency are inversely proportional

to find the speed we have to use the following equation

v = fλ

where v - speed, f - frequency and λ - wavelength

we have been given the period (T) so we have to find frequency (f)

f = 1/T

f = 1 / 20 s = 0.05 s⁻¹

v = 0.05 s⁻¹ x 200 m

v = 10 m/s

the speed of the wave is 10 m/s

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.