The Photogate has a beam of infrared light that travels from one side to the other. It can detect whenever this beam is blocked. You will drop a piece of clear plastic with evenly spaced black bars on it, called a Picket Fence.

The purpose of this lab was to measure the acceleration of a free falling object by using the slope of a velocity vs. time graph.

approximately 9.8 m/s2
The value of the gravitational acceleration is approximately 9.8 m/s2. In this experiment you drop a “picket fence” (a clear plastic strip with uniformly spaced opaque bands) through a photogate.

The Photogate works by projecting an infrared beam to a sensor. When the beam is blocked the sensor stops sending a signal, which illuminates an LED on the top of the gate as well as triggering the data collection software to display a blocked message in the data collection area.

Picket Fences have eight opaque bars spaced every 5 cm, silk-screened directly onto clear plastic. Drop the picket fence through a photogate to obtain records of position, velocity and acceleration vs time or to measure g. ORDER CODE: PF.

2. 2 votes. The picket fance problem occurs when an object is not aligned with , or does not fit into , the pixel grid properly.

In the first equation above, g is referred to as the acceleration of gravity. Its value is 9.8 m/s2 on Earth. That is to say, the acceleration of gravity on the surface of the earth at sea level is 9.8 m/s2.

Initial velocity is independent of the slope of the graph; that is, the acceleration. An object thrown downward still accelerates after release at the same rate as an object that is dropped.

Photogate timers are commonly used in physics laboratories to determine the velocity of a passing object. In this application a card attached to a moving object breaks the beam of the photogate timer providing the time for the card to pass.

Photogates are a timing device that measure times of the changes in state of an infrared beam that is blocked by a flag of known length, as well as the times the beam is unblocked. Using the flag length, and the blocked time, students can calculate speed.

Photogates allow for extremely accurate timing of events within physics experiments, for studying free fall, air track collisions, pendulum periods, the speed of a rolling object, among other things. The Vernier Photogate includes an accessory rod for mounting to a ring stand.