A.when the velocity at a given point changes steadily with time
B.when the velocity at a given point does not change with time
C.when the velocity does not change with respect to space
D.when the velocity be changed
A.when the velocity at a given point changes steadily with time
B.when the velocity at a given point does not change with time
C.when the velocity does not change with respect to space
D.when the velocity be changed