Question

The Earth rotates from west to east. A wind mass begins moving due north from the equator, along the Earth's surface. Neglect all effects other than the rotation of the earth. The wind mass will

• A. Always move due north
• B. Shift a little to the east as it moves to higher latitudes
• C. Shift a little to the west as it moves to higher latitudes
• D. Move along a loop and return to its starting point on the equator.

Answer 1

Answer: (B)

Shift a little to the east as it moves to higher latitudes

Answer 2

Due to the rotation of the earth about its axis, different points on its surface have the same angular velocity but different linear velocities, which is maximum at the equator and decreases at higher latitudes.

The earth rotating from west to east imparts an eastward velocity to the wind mass. The wind mass moving northward from the equator retains its eastward velocity, which is greater than the eastward velocity of the surface at higher latitudes. Hence, relative to the earth’s surface the wind mass shifts to the end.