Mechanics formulas

Acceleration

Calculate average acceleration, change in velocity, or elapsed time from motion along one axis.

Formula

a=Δvt a = Δv / t

Average acceleration is the change in velocity divided by the elapsed time.

Acceleration calculator

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Known values

The result updates automatically.

Result

5 m/s²

Substitution and calculation

a = Δv / t = 20 m/s / 4 s = 5 m/s²

Symbols and units

SymbolQuantitySISupported units
aaverage accelerationRate of change of velocity over the interval.m/s²m/s², km/h/s, km/h²
Δvchange in velocityFinal velocity minus initial velocity along the selected axis.m/sm/s, km/h
telapsed timeDuration of the velocity change.ss, min, h

Formula rearrangements

Calculate acceleration

a = Δv / t

Calculate change in velocity

Δv = a × t

Calculate time

t = Δv / a

Worked examples

Car accelerating from rest

A car changes its velocity by 20 m/s in 5 s. Find its average acceleration.

  1. 1Step 1: Use a = Δv / t.
  2. 2Step 2: Substitute Δv = 20 m/s and t = 5 s.
  3. 3Step 3: Divide 20 by 5 to obtain 4 m/s².

Result: 4 m/s²

Velocity change over eight seconds

An object has an average acceleration of 2 m/s² for 8 s. Find the change in velocity.

  1. 1Step 1: Use Δv = a × t.
  2. 2Step 2: Substitute a = 2 m/s² and t = 8 s.
  3. 3Step 3: Multiply 2 by 8 to obtain 16 m/s.

Result: 16 m/s

Sources and review