Here's a breakdown:

* Earth's Rotation: The Earth rotates on its axis once every 24 hours, completing a full revolution. This rotation speed is quite fast (about 1,000 miles per hour at the equator), but it's a constant speed.

* Inertia: Inertia is the tendency of an object to resist changes in its motion. This means objects in motion want to stay in motion at the same speed and direction.

* We're Moving with Earth: We, along with everything on the Earth's surface, are moving at the same speed as the Earth's rotation. Since we're moving with the Earth, our inertia keeps us moving in the same direction as the Earth spins, preventing us from being flung off.

Think of it like this:

Imagine you're in a car traveling at a constant speed. You're not thrown back against your seat because you're moving at the same speed as the car. Similarly, we're not flung off the Earth because we're moving at the same speed as the Earth rotates.

Important Note: If the Earth were to suddenly stop rotating, we would be thrown off the surface due to inertia. However, this is not a realistic scenario.