<span>Velocity is a vector and it has both speed and direction. It takes a force to change direction just as it does to change speed</span>. In order to have a constant velocity the object must maintain a constant direction and speed. Hope this answers the questions. Have a nice day.
I believe the answer is chemical reactivity because: Characteristics such as melting point, boiling point, density, solubility, color, odor, etc. are physical properties.
