Acceleration
Summary
- Acceleration is the rate of change of velocity with time.
- As a vector it must be stated with both magnitude and direction.
- Acceleration occurs anytime an object's…
- speed increases,
- speed decreases, or
- direction of motion changes.
- Average acceleration…
- is measured over a non-zero time interval and
- is represented by the symbol aave or a̅ (overline)
- Instantaneous acceleration…
- is the limit of average acceleration as the time interval approaches zero,
- is the first derivative of velocity with respect to time,
- is the second derivative of displacement with respect to time, and
- is represented by the symbol a (boldface)
- The various forms of acceleration are defined by the following equations…
average
accelerationa̅ = Δv Δt instantaneous
accelerationa = lim Δv = dv = d2s Δt→0 Δt dt dt2 - The SI unit of acceleration is the meter per second squared [m/s2]
- The acceleration due to gravity…
- is a natural unit of acceleration,
- is represented by the symbol g (roman),
- is equal to 9.80665 m/s2 by definition,
- is often rounded to 9.8 m/s2 for convenience, and
- is sometimes called the "g force" even though it is not a measure of force.