No, objects on Earth do not always move with constant velocity. In fact, most objects on Earth are subject to various forces that can cause them to accelerate, decelerate, or change direction. The concept of constant velocity refers to an object's motion when its speed and direction remain unchanged over time.
On Earth, objects are influenced by gravitational forces, friction, air resistance, and other factors that can affect their motion. For example, when you throw a ball into the air, it initially moves upward, then slows down due to the gravitational force pulling it downward, and eventually falls back to the ground. Similarly, when you push a car, it accelerates initially but then slows down due to friction and air resistance.
In the absence of external forces, an object in motion will continue to move with a constant velocity. This is described by Newton's first law of motion, also known as the law of inertia. However, in real-world situations, external forces are typically present, leading to changes in velocity and making constant velocity rare in everyday experiences.