Education and Manpower Bureau
Using Datalogger in the Teaching of Physics

Acceleration of a Dynamics Cart

Experiment Profile:

1. Objective

 To measure the acceleration of the cart as it moves down an inclined plan. To illustrate if the acceleration of the cart is constant.

2. Equipment List

 Datalogger interface connected to a PC Motion sensor Dynamics cart Air track Boxes of different heights Protractor

 Experiment Collision and Conservation of Momentum Simple Harmonic Motion Acceleration due to Gravity Pushing and Pulling a Dynamics Cart Acceleration of a Dynamics Cart

 Procedure.

 1 Connect the datalogger interface to a PC with the software installed. 2 Use a box placed under the air track to raise the track at one end. 3 Connect the motion sensor to the interface and fix it at the high end of the air track. 4 Before data recording, make sure the motion sensor is aligned and can record the movement of the cart. 5 Place the cart at the low end of the track. 6 Start the data-logging software to collect data. 7 Give a firm push on the cart up the air track so the cart will move up the inclined plane toward and then away from the motion sensor. Please note that the cart cannot go too close to the motion sensor which is less than the minimum distance of the motion sensor. 8 Stop the data collection when the cart returns to the bottom of the air track.

Analysis:

 1 Record the angle of the track using a protractor. 2 Plot a velocity versus time graph using the data collected. Find out the slope of the line from the collected data. 3 Describe the velocity versus time graph. 4 Describe the acceleration versus time graph. 5 Find out the mean acceleration from the collected data. 6 How does the acceleration determined in the plot of velocity compare to the mean value of acceleration from the plot of acceleration?

Extensive:
Try to change the angle of the air track using boxes of different heights. Is the result the same? If yes, please explain.

 Acknowledgements We are particularly grateful to Carmel Pak U Secondary School for their help in the production of this video.

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