* Work and Energy: Work is the transfer of energy. When work is done on an object, its energy changes.
* Kinetic Energy: An object's kinetic energy is the energy it possesses due to its motion. It's directly related to its velocity: Kinetic Energy (KE) = (1/2) * mass * velocity²
* Work-Energy Theorem: The work-energy theorem states that the net work done on an object equals the change in its kinetic energy.
Therefore, if no work is done (net work = 0), the change in kinetic energy is zero. This means the object's velocity remains constant.
Important Considerations:
* This applies to the object's *net velocity*. If forces are acting on the object but they balance out (like gravity and air resistance), its velocity might be constant even though work is being done by those forces.
* We're talking about net work. Even if some work is done, if it's canceled out by other work, the net work is zero, and velocity will remain constant.
Example:
Imagine a ball rolling on a perfectly smooth, frictionless surface. No work is being done on the ball (no force is acting to change its motion), so it continues rolling at the same speed and direction forever.
