What is acceleration defined as?

Acceleration is defined as the change in velocity over time, which is typically expressed in meters per second squared (m/s²). While option C states "the change in velocity in 1 second," it captures the concept of acceleration, as acceleration is fundamentally concerned with how velocity changes within a given time interval. For instance, if an object's velocity increases from 0 m/s to 10 m/s in 2 seconds, we can calculate the acceleration by looking at the change in velocity over the time taken.

In contrast, the first option focuses solely on the rate of change of speed without accounting for direction, which does not encompass the full definition of acceleration since velocity is a vector quantity (it includes both speed and direction). The second option, "the increase in velocity over time," does not accurately represent acceleration, as it leaves out the notion of how quickly that increase occurs and could imply just a simple increase rather than the specific rate. The fourth option describes distance covered, which is a different measurement altogether and does not address velocity or acceleration at all. Therefore, understanding that acceleration specifically involves changes in velocity over time is key to grasping this fundamental concept in physics.