A foam cooler of negligible mass contains 1.75 kg of water. Ice from a refrigerator at −15°C, is then added to the water in the cooler. When thermal equilibrium has been reached, the total mass of ice in the cooler is 0.778 kg. Assuming no heat exchange with the surroundings, what mass of ice was added? For water, Lf = 334 × 103 J/kg, and for ice, ci = 2100 J/(kg • K).

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.

d

explanation:

v=uf/(u-f)

= 5.10/(5-10) convex lens has positive focal length

=50/-5

=-10 cm (formed at other side)