1.3 - Acceleration
The formula for acceleration
Where:
- = Acceleration, in metres per second squared (m/s2)
- = Final velocity, in metres per second (m/s)
- = Initial velocity, in metres per second (m/s)
- = Time taken, in seconds (s)
The change in velocity is the final velocity minus the initial velocity ().
Worked example - Time for a given acceleration
A cyclist accelerates at 1.5 m/s2 from 3.0 m/s to 7.5 m/s. Find the time it takes to do this.
Step 1 - Rearrange the acceleration equation for time
Step 2 - Substitution and calculation
Free fall and the acceleration of free fall
- In the absence of air resistance, all objects fall at the same rate regardless of their mass.
- An object dropped from rest speeds up as it falls - its speed increases by about 10 m/s every second.
- The steady acceleration of an object falling freely from rest is called the acceleration of free fall, g. Near the Earth's surface its value is about 10 m/s2.