Awaterfall is 145 m high.

what is the increase in water temperature at the bottom of the falls if all the initial potential energy goes into heating the water? (g = 9.8 m/s2, cw = 4 186 j/kg⋅°c)

a. 0.16°c
b. 0.34°c
c. 0.69°c
d. 1.04°c

Explanation:

Given

height from which water is falling

heat capacity of water

here Potential Energy is converted to heat the water

i.e.

the old price per ounce is c/4.

the new price per ounce is c/3.6.

the ratio of the old price to the new one is

(c/4)/(c/3.6) = (c/c)×(3.6/4) = 0.9 . . = 9/10 . . "nine tenths" in either form