The two different isotopes have weights :
w1 = 78.918 amu
w2 = 80.916 amu
average weight w3 = 79.903 amu
The mixing of two components can be modeled as
let the fraction of w1 be 'x'
hence 
now this is a linear equation in 'x'. Substituting the values we get
x = 0.507
hence the percentage of Br79 = 50.7% and the percentage of BR81 = 49.3%
The appropriate answer is c. geysers. A geysers a hot water fountain that spouts intermittently with great force, frequently accompanied by a thunderous roar. The world famous Old Faithful is located in Yellowstone National Park. This geyser erupts every 65 min sending a jet of water almost 60 meters into the air. Sinkholes and caves are formed by the action of groundwater on carbonate rocks which causes them to colapse and former these structures.
There would be no mass or weight and he would float away
Answer:
5 weeks and 5 days is required to empty the lake
Explanation:
Officials begin the remove water from a full man made lake
The lake can be emptied in 4 weeks
= -1/4
A river can fill the lake up in 15 weeks
= 1/15
Let t represent the number of weeks that is required to empty the lake
= -1/t
Therefore the number of weeks it takes to empty the lake can be calculated as follows
-1/t= -1/4 + 1/15
-1/t= -11/60
Cross multiply
-11×t= -1×60
-11t= -60
t = 60/11
t= 5 5/11
Hence it takes 5 weeks and 5 days to empty the lake
The acceleration of the car will be needed in order to calculate the time. It is important to consider that the final speed is equal to zero:
We can clear time in the speed equation:
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