Question

On account of the earth rotating about its axis:-

• A. the linear velocity of object at equator is greater than at other places.
• B. the angular velocity of object at equator is more than that of objects at poles
• C. the linear velocity of objects at all places at the earth is equal , but angular velocity is different
• D. at all places the angular velocity and linear velocity are uniform

Answer 1

Answer: (A)

the linear velocity of object at equator is greater than at other places.

Let us consider a point on the equator and point in a higher or lower latitude. Which one will describe a bigger circle on rotation? Yeah, the one on the equator. Now the time of rotation is the same for both $24$ hours. So the one describing a greater circle obviously will have to move at a higher speed, or more correctly tangential velocity.

The more technical version would be that all points on the surface of Earth has the same angular velocity, from the definition of rigid body. Tangential velocity is related to angular velocity as$“v=r.w”$ where ‘v’ is tangential velocity, ‘w’ is angular velocity and ‘r’ is the radius at a certain point. From this equation, we can see that velocity depends on the radius and since radius increases as we go towards the equator and decreases away from it, the velocity also varies in the same way.