What is the difference between uniform and non-uniform motion?

When an object moves in a straight line at constant speed, we say that it has uniform motion. The distance travelled by an object in uniform motion increases linearly. If you ride your bike at constant speed in a straight line, you cover distance steadily.

Þ  Sketch the d-t graph for an object in uniform motion below.

position
time
We recall that the slope of the d-t graph gives the object's speed.
Þ  a steep line means…
Þ  a flat line means…
Þ  the units of the slope are…
Þ  a negative slope means…

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What do you think is meant by the term non-uniform motion?


A basketball rolling along a floor moves uniformly. A basketball bouncing off the floor moves non-uniformly.

1.  Make digital movies of a basketball in uniform and in non-uniform motion.

2.  Use Fathom and RealPlayer to collect position-time (d-t) data for the moving objects.

3.  Draw d-t graphs to represent the motion of each.

4.  The slope of the d-t graph gives the rate of change of the position with respect to time, or the velocity. Use the d-t graphs to draw the v-t graph.

5.  The slope of the v-t graph gives the rate of change of the velocity with respect to time, or the acceleration.

6.  Use graphs of the position, velocity, and acceleration of the rolling and falling balls to describe their motions.

Report:

Introduction:

§  Define and describe the motion of an object in uniform and in non-uniform motion.

§  Compare the position–time and velocity–time graphs of objects in uniform and non-uniform motion.

§  How can you determine the acceleration of the ball in each case?

§  We are going to use the graphs of objects in motion to describe uniform and non-uniform motion

Method:

§  What did we do?

§  How did we do it?

Results:

§  Paste in the position-time and velocity-time graphs for the uniform and for the non-uniform motion.

Discussion:

§  Characterize uniform and non-uniform motion based on your experimental findings.