Question

which statement correctly describes the differences between positive and negative acceleration? positive acceleration describes a change in speed; negative acceleration describes no change in speed. positive acceleration describes no change in speed; negative acceleration describes a change in speed. positive acceleration describes an increase in speed; negative acceleration describes a decrease in speed. positive acceleration describes a decrease in speed; negative acceleration describes an increase in speed.

Explanation:

To determine the correct statement, recall the definitions of positive and negative acceleration. Acceleration is the rate of change of velocity (which includes speed and direction, but for the basic concept here, we focus on speed change). Positive acceleration occurs when an object's speed increases (in the direction of motion or when the change in velocity is positive), and negative acceleration (deceleration) occurs when an object's speed decreases (opposite to the direction of motion or when the change in velocity is negative).

• The first option is wrong because negative acceleration does involve a change in speed (decrease).
• The second option is wrong as both positive and negative acceleration involve a change in speed (positive is increase, negative is decrease).
• The third option matches the definitions: positive acceleration is an increase in speed, negative is a decrease.
• The fourth option swaps the definitions, which is incorrect.

Answer:

C. Positive acceleration describes an increase in speed; negative acceleration describes a decrease in speed.