Mixed Velocity-Time Graphs

Back to Physics Grade 9/10


This is a simple physics tutorial aimed at high school students in grades 9 and 10 (GCSE, HSC) exploring velocity-time graphs.

Multiple Legs in a Velocity-Time Graphs

Like Distance-Time graphs, it's possible to include multiple portions of a journey on a velocity-time graph. The graph below illustrates three different portions of a journey, in green, pink, blue.

As you'll see below, each leg illustrates a different type of acceleration.

Portion 1

The initial velocity (0 m/s) and calculated acceleration (2.5m/s˄2) have the same sign (both +). This means that the first portion depicts a journey that's involved acceleration.

Portion 2

The calculated acceleration is 0m/s˄2. This means that the second portion depicts a portion of the journey where there has been no acceleration i.e. no change in velocity. This means that the object is traveling at a constant velocity at this time. We can tell from the graph that this constant velocity is 10 m/s.

Portion 3

The initial velocity (+10 m/s) and the calculated acceleration (-5m/s˄2) have got opposite signs (+ and -). This means that the third portion depicts a journey that's involved deceleration.