Acceleration Due to Gravity Labwith 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 Capstonedisplay 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.
  1. 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.
  1. 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 between the leading edge of each opaque band, Capstonecalculates 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

Data Tables Do not write units in data cells. Use appropriate sig figs.

Table 1: Motion Sensor

Trial / Acceleration (m/s2) / Percent Deviation (%)
1
2
3
4
5
Average

Table 1: Stopwatch and Ball

Trial / Time (s) / Acceleration (m/s2) / Percent Deviation (%)
1
2
3
4
5
Average

Table 3: Picket Fence

Trial / Acceleration (m/s2) / Percent Deviation (%)
1
2
3
4
5
Average

1