Velocity is the speed of an object moving in a definite direction. The velocity of an object can be uniform or variable. When an object moving along a straight line at variable speed, we can Express the magnitude of its rate of motion in terms of average velocity.
Average velocity=Initial velocity+Final velocity/2
The SI unit of velocity is m/s.
Not directly. Detectors can convert to a form that is visible to the human eye. Hope that helps
Because they are non renewable sources of energy and they took billions of years to form.