Acceleration Due to Gravity Lab with Formal Lab Report
Purpose
The purpose of this lab is to measure the acceleration due to gravity of a falling object
assuming that the only force acting on the object is the gravitational force.
You will also be evaluating the accuracy and precision of three different experiments.
Background
Neglecting air resistance, an object falls a distance proportional to the square of the time.
d  t2
Galileo was the first to derive this mathematical relationship. He asserted that for a given
location on Earth, all objects fall with the same uniform acceleration. This acceleration is
commonly referred to as the acceleration due to gravity, and is given the symbol g. This
value is g = 9.80 m/s2.
Procedure
You will be measuring the acceleration due to gravity (g) in three ways. Each lab group will
perform three different experiments from the following list.
1. Motion Sensor: Hang a motion sensor from the ceiling. Drop a ball and have Capstone
display a velocity vs. time graph. The slope of the line is the acceleration. PRINT A GRAPH
WITH THE EQUATION DISPLAYED FOR EACH PERSON IN YOUR GROUP.
2. Stopwatch and Ball: Measure the distance from ceiling to floor. Drop a ball and record the
time with a stopwatch. The acceleration can be calculated by the formula a = (2d)/t2.
3. Picket Fence: Drop a Picket Fence (a clear plastic strip with uniformly spaced opaque bands)
through a Photogate. Each opaque band on the Picket Fence blocks the Photogate beam and
the time from one blockage to the next becomes increasingly shorter. Knowing the distance
1
between the leading edge of each opaque band, Capstone calculates the acceleration of the
picket fence. Display and record the acceleration. You do not need a printout.
Instructions

Remember to measure and record your data accurately and precisely (to the correct
amount of significant digits).

Record your data on the following data tables. Recreate these tables in your lab report.

Calculate the percent error for your experiment and include this in your data tables. This
is a measure of your accuracy. The accepted value for g is 9.80 m/s2. The formula is:
percent error =  average acceleration – 9.80 m/s2  x 100
9.80 m/s2
***Remember to record the absolute value of percent error and percent deviation.***

Calculate the percent deviation for your experiment and include this in your data tables.
This is a measure of your precision. The formula is:
percent deviation =  measured value – average value  x 100
average value
Questions to Be Answered in Lab Report
1. What was your average g for each experiment?
2. Which activity had the best precision? How do you know?
3. Which had the best accuracy? How do you know?
Remember to attach a rubric to the end of your lab report. DO NOT TURN IN THIS LAB
HANDOUT
2
Data Tables
Do not write units in data cells. Use appropriate sig figs.
Table 1: Motion Sensor
Acceleration
Trial
(m/s2)
Percent
Deviation (%)
Percent Error =
1
2
3
4
5
Average
←average the columns:
trial 1 + trial 2 + ….
5
Table 1: Stopwatch and Ball
Trial
Time (s)
Acceleration
(m/s2)
Percent
Deviation (%)
1
Percent Error =
2
3
4
5
Average
Table 3: Picket Fence
Acceleration
Trial
(m/s2)
Percent
Deviation (%)
Percent Error =
1
2
3
4
5
Average
3