The correct answer is - Positive acceleration describes an increase in speed; negative acceleration describes a decrease in speed.
Answer:
Positive acceleration describes an increase in speed; negative acceleration describes a decrease in speed.
Explanation:
Acceleration is defined as:
[tex]a=\frac{v-u}{\Delta t}[/tex]
where
v is the final velocity
u is the initial velocity
[tex]\Delta t[/tex] is the time taken for the change in velocity to occur
The value of [tex]\Delta t[/tex] is always positive, so the sign of the acceleration depends on the numerator. More specifically, we have two situations:
- if [tex]v > u[/tex], then it means that the final velocity is greater than the initial velocity, so the acceleration is positive and the speed is increasing
- if [tex]v < u[/tex], then it means that the final velocity is smaller than the initial velocity, so the acceleration is negative and the speed is decreasing
