There are few reasons <span>why mercury is used in liquid barometer instead of water:
1. </span>Mercury (13.69 g/cm³) is more dense than water (1.00 g/cm³), so if we use water in barometar, <span>length of barometer would be much longer.</span><span>
2. </span><span>Mercury has lower vapor pressure than water.
3. </span>Mercury has lower freezing point (-38.83°C) than water (0°C)<span>.
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Answer: D) 36.0 km/hr, downstream
Explanation:
For downstream motion of the boat, the actual velocity of the boat is the sum of velocity of the water current and the velocity of the boat due to pushed by wind.
Velocity of water current, v = 15 km/h
Velocity of the boat going downstream, u = 21 km/h
Actual velocity of the boat = v'
v' = v + u
⇒v' = 15 km/h + 21 km/h
⇒u = 21 km/h +15 km/h = 36.0 km/h downstream
Thus, the correct answer is option D.
The Answers is D because cell division purpose is grow and repair