Which of the following statements are true for a moving body?

Options

A. If its speed changes, its velocity must change and it must have some acceleration
B. If its velocity changes, its speeds must change and it must have some acceleration
C. If its velocity changes, its speed may or may not change, and it must have some acceleration
D. If its speed changes but direction of motion does not change, its velocity may remain constant

Answer

A, C

Explanation

`vec(v)=|vec(v)|hat(v), " "[|vec(v)| rarr "speed"]`
Velocity may charge by changing either speed or direction and by both.