What are the function of mercury barometer ​

A mercury barometer is an instrument used to measure atmospheric pressure in a certain location and has a vertical glass tube closed at the top sitting in an open mercury-filled basin at the bottom. Mercury in the tube adjusts until the weight of it balances the atmospheric force exerted on the reservoir.

Explanation:

1. The density of mercury (=13.6×10 to power 3 kg /m) is greater than that of any other liquid so only 0.76m height of mercury column is needed to balance the normal atmospheric pressure. Use of other liquids require much longer tube .

2.The vapour pressure of mercury is negligible, and so the vacuum does not affect the barometric height.

3.The mercury neither wets nor sticks to the glass tube therefore gives accurate reading.

4.It can easily be obtained in a pure taste .

5. Mercury has a opaque and shinning surface therefore can me easily seen while taking the reading.

Explanation:

A mercury barometer is an instrument used to measure atmospheric pressure in a certain location and has a vertical glass tube closed at the top sitting in an open mercury-filled basin at the bottom. Mercury in the tube adjusts until the weight of it balances the atmospheric force exerted on the reservoir.

the total distance that martina travels that day is

(distance from home to mom's office) plus (distance from mom's office to school)

plus (distance from school to library) plus (distance from library to friend's house)

plus (distance from friend's house to martina's house).

(we don't know what any of these distance actually is.)

total distance/total time

(85 + 82)/(5+3)

167/8

20 just over