Question

A plane is flying at the height of $5000 m$ above the sea level. At a particular point, it is exactly above a submarine floating $1200 m$ below the sea level. What is the vertical distance between them?

Answer 1

Hint: The height above the sea level is taken as positive and the height below the sea level is taken as negative. For the measurement of vertical distance between them we take the modulus of the negative height and then add both the heights.

Complete step by step answer:
Given the height of the plane is 5000 m above the sea level.
Let us denote this height with ${h_1} = + 5000m$.
The depth of the submarine below the sea is 1200 metres below the sea level.
Let us denote this distance with ${h_2} = - 1200m$
Since this distance is below the sea level we take the modulus.
$
D = {h_1} + |{h_2}| \\
\Rightarrow D = 5000 + | - 1200| \\
\therefore D = 5000 + 1200 = 6200m \\
$
Therefore the vertical distance(D) between the plane and the submarine is 6200m.

Additional information:
The instrument used for measuring the height of any place is known as a barometer. At sea level the level of mercury in the barometer is 76 cm. ‘Above the sea level’ shows an elevation from the general average level and ‘below the sea level’ shows the depression from the average level.

Note: In general the distance below the sea level is taken as negative. To find the vertical distance of any object below the sea level we take the modulus of the distance of the object from the sea level. Sea level is the average level of earthly water bodies on the surface of the earth which is taken as reference to measure the height of any elevation or depth.