Set up a pulley timer

Use the pulley timer linear measurements to measure the position, speed, and acceleration of a cart on a track or a mass on an Atwood's machine. Use the rotational measurements to measure the angle, angular speed, and angular acceleration of a rotating object.

Equipment setup

• Photogate

  Use a Wireless Smart Gate (PS-3225), a Smart Gate (PS-2180) with a PASPORT interface, or a Photogate Head (ME-9498A) with a digital interface.

• Super Pulley (ME-9433)

  Clamp the Super Pulley to the end of a track (as shown below), to a ring stand, or to a rotational apparatus.

Set up the timer

1. Connect your chosen photogate to Capstone.
2. Select Timer Setup from the Tools palette.
3. At the top of the Timer Setup tool, click the Delete button to delete the premade Smart Timer.
4. Select Pre-Configured Timer, then click Next.
5. Ensure that exactly one photogate is selected from the list of available timing devices, then click Next.
6. Select Photogate with Pulley from the list of available timers.
7. Check the box for each measurements you want to be visible, then click Next.

8. Measure the Spoke Arc Length and Spoke Angle, as described below. Enter these parameters into the corresponding text boxes, then click Next. (Note that the default values are equal to the Super Pulley parameters.)

   • Spoke Arc Length: Equal to the circumference of the pulley's inner grove divided by the number of spokes.
   • Spoke Angle: Equal to 360° divided by the number of spokes.

   

9. Give the timer a custom name, or use the default name, and click Finish.

Record data

Click Record , then spin the pulley. The software records a measurement each time the pulley blocks and then unblocks the photogate beam. Speed requires two initial passes, and acceleration requires three initial passes, before the first measurement is recorded.