what are the different ways in the velocity of a body can be changed?
Answers
Explanation:
Only a mechanical force can change the velocity of a body as determined by an inertial frame according to special relativity. Let me say this in a more precise manner.
An observer that is using an inertial frame, the ONLY way to change the velocity of a body is to apply a mechanical force to the body that is a nonzero vector. This will be true under all conditions where special relativity is valid.
Types of mechanical force include electromagnetic forces, strong nuclear forces, weak nuclear forces, contact forces, frictional and centripetal forces. There is some overlap in this list because it encompasses different length scales. However, the overlap is not important for relativity. Mechanical force does not include gravity or any other inertial force.