Physics Lab Kinematics

Physics Lab – Kinematics Name: ______Period: ______

Motion – Chaos in a Straight Line

Purpose: To investigate the motion of a marble along a horizontal track. You will use the knowledge gained in the first part of this lab to complete a performance challenge in the second part.

Predictions:

Before we take ANY data it is very important to think about what the outcome of this investigation will be. You will be taking measurements of velocity at regular distances– as if you looked down and recorded your velocity every mile as you drove along on “cruise control” in your car. Please draw the shape you would expect to see for the marble as it travels along the horizontal track. Don’t worry about numbers right now – just try to draw the shape of the graph you expect to see on the graph below.

Velocity (m/s)

Distance from bottom of ramp (m)

Materials:

Lab part number needed ball drop 1 long straight 5 long tube 2 short tube 7 flex track 1 ball connector 2 5 way joint 6 Cross beam connector 2 yellow marble 1

Procedure:

Set up a Chaos tower track so that there is a short ramp to accelerate the marble as well as a long (approx. 1.5 meter) flat section for the rollout (see picture above). It is critically important that this ram and roll-out are not changed in any way during this experiment. Consistency is the key to getting good data and also scoring highly on the performance challenge in the second half of the lab. We will only be measuring the marble as it rolls along the FLAT today – ramps involve gravity and we don’t even know what that word means yet! How can you make sure your flat section is REALLY flat? Set the velocity detector at evenly spaced intervals along the flat section and measure the velocity of the marble three times at each spot. Be careful to release the marble the same way from the same height each time.

Use the data table below:

Distance Velocity (m/s) from bottom of ramp (m) Trial one Trial two Trial three AVG. 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

Graphing your data:

Make a graph of the distance (in meters) vs. average velocity (meters per second). Make sure to label the x and y axis and also put a title at the top of your graph. When your graph is done show it to your teacher and then answer the following questions:

1) How did your graph compare to your estimate?

2) What was similar?

3) What was different?

4) Describe the shape of your graph in detail and explain why you think it has that shape.

Performance Challenge:

Now that you have a graph that gives you a picture of the behavior of the marble along the horizontal track, you will use your graph to make a prediction…a prediction that will in part determine your grade for this lab. Each group will be randomly assigned a distance and then will have to predict the TIME it will take their marble to travel that distance. Scoring will be based on the % difference between your estimated time and the actual time measured by your teacher. The scoring table is shown below:

% Difference Points < 5 5 < 10 4 < 15 3 < 25 2 < 40 1