GOAL

To calculate the acceleration of an object rolling down an inclined plane.

INTRODUCTION

Acceleration is the change in the velocity of an object. Velocity is a vector quantity with both direction and magnitude. Acceleration is also a vector quantity with both direction and magnitude. If the speed of an object is changed, that object has accelerated either positively or negatively depending on whether it increased or decreased in speed. Another way to accelerate an object is to change its direction of movement. This means that a car going around a corner is undergoing acceleration because its velocity in terms of direction is changing even if the car's speed, as seen on the speedometer, is constant.

As discussed above, an object falling under the influence of gravity accelerates. From your studies, you can recall the key kinematic equations for the uniformly accelerated motion of an object starting from rest, where v = velocity, a = acceleration, and d = distance.
Using these equations it is then possible to solve for the unknown variables.

In this lab experiment, we will measure the time it takes for a marble to roll down an inclined plane. From the experimental data, we will then estimate the value of gravity (g).

INITIAL PARAMETERS

QUESTION 1: What is the distance between two marks in your inclined plane?

QUESTION 2: What is the angle of your inclined plane with respect the horizontal? (0° would mean the inclined plane totally horizontal, so the ball would not move; 90° would mean the board totally vertical)

Write down these two values in the table we will use to record all our measurements. It will also be used at the end of the lab.

ANALYSIS OF RESULTS

QUESTION 3 : Newton's first law says a body at rest will remain at rest unless acted upon by an outside force, and a body in motion will continue in motion at the same speed and in the same direction unless acted upon by an outside force. What forces were acting on the marble as it traveled down the ramp?

QUESTION 4 : Did the measured acceleration was about the same for the three (or four) sections of the experiment (Release point to 1st marking, to 2nd marking, etc) ?

QUESTION 5 : Do you expect this acceleration to be constant or different for the three (or four) sections of this experiment? Explain your reasoning.

QUESTION 6 : By looking at the Standard Deviation results for the calculated acceleration, which section of this experiment is the more precise? Explain your reasoning.

QUESTION 7 : What was the average value of acceleration for the most precise section of this experiment?

QUESTION 8 : Intuitively, we can understand that the velocity (and therefore the acceleration) of the ball will increase as we increase the angle of the inclined plane. We can make the assumption that the acceleration of the ball is equal to:

Expected acceleration = (5/7)gsin(θ) where g=9.8 m/s2

The angle of the inclined plane is the value that you measured in Question 2 and transcribed into the table. Using the measured value of the angle of the inclined plane, calculate the expected value of the acceleration.

QUESTION 9 : Calculate the relative error between the measured value of acceleration (from Question 7) and the expected value of acceleration (from Question 8).

QUESTION 10 : What do you think are the elements that may contribute to increasing this error? How would you solve them?

LABORATORY REPORT

Create a laboratory report using Word or another word processing software that contains at least these elements:

Introduction: what is the purpose of this laboratory experiment?

Description of how you performed the different parts of this exercise. At the very least, this part should contain the answers to questions 1-10 above. You should also include procedures, etc. Adding pictures to your lab report showing your work as needed always increases the value of the report.

Conclusion: What area(s) you had difficulties with in the lab; what you learned in this experiment; how it applies to your coursework and any other comments.