# Average Acceleration Formula

Acceleration is the rate of change for velocity, that is, change in velocity over a specified period of time. Average acceleration is the final velocity minus the initial velocity per time taken.

A_{avg} = Δv / Δt

A_{avg} = Average acceleration, m/s^{2}

Δv = v_{f} - v_{i}, m/s

Δt = t_{f} - t_{i}, s

Average Acceleration Formula Questions:

1) Your friend's new car can go from 0 to 60 m/s in 7 sec. What is the acceleration?

Answer: The final velocity, v_{f} = 60 m/s; the initial velocity, v_{i} = 0; the final time, t_{f} = 7 sec; and the initial time, t_{i} = 0.

A_{avg} = Δv / Δt

A_{avg} = (60 m/s) / 7 s

A_{avg} = 12.86 m/s2

2) When driving along a side-road at 45 m/s, you see a child run out into the street, and rapidly slow to 3 m/s, within 1.5 sec. What is your acceleration?

Answer: The final velocity, v_{f} = 3 m/s; the initial velocity, v_{i} = 45 m/s; and the time, t = 1.5 sec.

A_{avg} = Δv / Δt

A_{avg} = (3 m/s - 45 m/s) / 1.5 sec

A_{avg} = (- 42 m/s) / 1.5 sec

A_{avg} = - 28 m/s^{2}

Notice, the negative sign, indicating the object slowed down.

Related Links: |