1. D. velocity
Explanation: Acceleration is best defined as the rate of change of velocity of an object. In fact, acceleration is defined as:
[tex]a=\frac{\Delta v}{\Delta t}[/tex]
where [tex]\Delta v[/tex] is the change in velocity of an object, while [tex]\Delta t[/tex] is the time taken for that change in velocity to occur. Keep in mind that a change in velocity means a change either in the speed of the object, or in its direction: so, for instance when an object moves at constant speed in a circle, it is also accelerating since its direction is changing, and so its velocity is also changing.
2. C. m/s2
Acceleration is measured in [tex]m/s^2[/tex]. In fact, acceleration is defined as
[tex]a=\frac{\Delta v}{\Delta t}[/tex]
where [tex]\Delta v[/tex] is measured in m/s, while [tex]\Delta t[/tex] is measured in s (seconds), so acceleration is measured in
[tex][a]=\frac{[m/s]}{[s]}=[\frac{m}{s^2}][/tex]
3. C. Velocity has both speed and direction
In fact:
- speed is a scalar, so it consists only of a magnitude, which is defined as the ratio between the distance traveled (d) and the time taken (t):
[tex]s=\frac{d}{t}[/tex]
- velocity is a vector, so it consists of both a magnitude (which is the speed) and a direction, which is given by the direction of motion.
