Purpose: To illustrate concepts of velocity and acceleration with quantitative measurements on a nearly frictionless surface.

Velocity of cart is determined by dividing the length d of a light-obscuring plate by the time t that the light remains obscured (v=d/t). The time is measured with the Pasco 750 interface. These accurate determinations of velocity are then used to show acceleration.

1. Download the DataStudio setup file 'M24_1.ds' to the desktop of the lecture computer. Start the Pasco DataStudio software by double clicking the setup file. Test the operation of the electronics by interposing hand between light source and photo-sensitive diode. There is a red LED on each of the photogates that will light when the gate is blocked. Explain operation to class and how to calculate velocity of cart.
   
2. Turn on blower and show from computer readings that the cart retains nearly constant velocity.
   
3. Raise one end of track using the elevation block and place the photogates 60 cm and 160 cm from start. Release cart and determine velocity at d=60 cm and d=160 cm. Calculate accelerations from constant acceleration equations.

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