1.5 know and use the relationship between acceleration, velocity and time: acceleration = change in velocity time taken

Formula:

acceleration = change in velocity
                            time taken

change in velocity = final velocity - initial velocity

Acceleration is the rate at which an object changes its speed. If the outcome is negative, it is a deceleration.

Acceleration is measured in m/s2
The formula can be rearranged:

change in velocity = acceleration x time taken

time taken = change in velocity
                         acceleration


Examples:

1. A car's speed changes from 5 m/s to 15 m/s in 10 seconds, what is it's acceleration. Which units will you use?
2. A van's speed changes from 2mph to 15 mph in 1 hour, what is it's acceleration. Which units will you use?
3. A motorbike's speed changes from 18 m/s to 12 m/s in 3 seconds, what is it's acceleration. Which units will you use?

Answers:

1.  1 m/s2
2. 13 mph2
3. -2m/s2