Bill and Ted are standing on a bridge 40 ft above a river. Bill drops a stone, while Ted decides to throw a stone downward at 10 m/s. How long after Bill released his rock should Ted throw his if they want the stones to hit the water simultaneously? Choose answer closest to calculated result. A. del t 15.5 sec B. del t 0.86 sec C. can not be determined. D. del t - 0.72 sec

D) - 0.72 secs

Explanation:

Parameters given:

Height of bridge = 40ft = 12.19 m

Initial velocity of Bill's stone = 0m/s

Initial velocity of Ted's stone = 10m/s

We find the time it take Bill's stone to bit the river and the time it takes Ted's stone to hit the river. Then we find the time difference.

Using one of the equations of motion:

For Bill:

S = ut + ½gt²

Where g = 9.8 m/s

12.19 = 0 + ½*9.8*t²

t² = 12.19/4.9 = 2.49

t = 1.58 secs

For Ted:

S = uT + ½gT²

12.19 = 10*T + ½*9.8*T²

=> 4.9T² + 10T - 12.19 = 0

Using quadratic formula and retaining only the positive value, we get that:

T = 0.86 secs

Time difference between Bill's throw and Ted's throw is:

0.86 - 1.58 = - 0.72 secs

In reality, this means that Ted must throw his stone 0.72 secs before Bill throws his for both stones to land the same time.

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.