## The Ball Rolling Down an Incline Experiment 11/24/2003

Below is a picture of our experiment. It shows a steel ball rolling down the inclined board with a slot to keep the ball from rolling off the edge. Here you see the ball rolling down the board. Notice that the board has been marked. Each of these marks are .1 meter apart. The board has been marked every .1 m from 0 to 1.2 m. [ Click here to watch a movie of the ball rolling down the incline. ]

Such that we can repeat the experiment if need and so that we can calculate the angle of the board, we noted how the board was resting on the table. Toward the right end to the board, the 1.2 m mark is resting on the table. Toward the left end of the board, the 0.2 m mark is resting on a stack of small boards. Below you can see the measurements concerning the inclined board. Note the board is propped up on the .2 meter mark and rests on the end of the table at the 1.2 m mark. The distance between the .2 m mark and the 1.2 meter mark is 1 meter. The height of the three small boards that prop up the inclined board was measured. Notice that this height is 5.6 cm. Please note these measurements such that the angle of the board can be determined later. The ball was rolled to each of the marks on the board and timed with a stop watch such as the one pictured here. Since no one can turn the stopwatch on and off perfectly, each time was measured three times. These times will be averaged in order to get a better measurement. Below are the times measured in 5th hour and 6th hour science class. We will do a lot more with this experiment, but the assignment for tomorrow (11/25/03) is to compute all of the average times and have them ready at the beginning of class. On 12-3-03 we also measured the mass of the ball that we used in this experiment. Since the ball would not stay on the balance we used a cup to keep it from rolling off. Here are the measurements of mass that we made.

 Using a Balance Measuring the Mass of the Cup  The mass of the cup was 5.5 g Measuring the Mass of the Ball in the Cup  The mass of the ball and cup was 35.1 g

5th Period Science Class
 Distance (m) Time (sec.) Average Time (sec.) 0 0 .1 .72 .72 .72 .2 1.00 1.00 1.04 .3 1.22 1.19 1.19 .4 1.41 1.44 1.38 .5 1.59 1.59 1.63 .6 1.78 1.75 1.69 .7 1.87 1.91 1.90 .8 2.06 2.06 2.07 .9 2.12 2.16 2.19 1.0 2.28 2.29 2.29 1.1 2.43 2.39 2.44 1.2 2.50 2.50 2.53

6th Period Science Class
 Distance (m) Time (sec.) Average Time (sec.) 0 0 .1 .75 .69 .71 .2 .96 1.00 1.00 .3 1.16 1.25 1.22 .4 1.44 1.38 1.38 .5 1.62 1.60 1.59 .6 1.75 1.72 1.72 .7 1.91 1.94 1.88 .8 2.06 2.03 2.00 .9 2.19 2.16 2.19 1.0 2.25 2.28 2.25 1.1 2.40 2.37 2.44 1.2 2.53 2.47 2.53

You should find your own average times by adding the three time measurements and dividing by 3 for each distance mark on the board. You may now (as of 11-28-03) check your calculations here using this web site. Be sure you have the time measurements on your paper. You will need them to use this next page.

Because we could not calculate acceleration in our experiment using what we know from the book, Mr. B has discovered another formula that will help. Therefor this next web page will also calculate acceleration values if you enter the correct time measurements.

Click here to go to next page for making calculations of average time and acceleration.

### Questions

Will a ball roll down a board with a constant acceleration? What is the accelleration for the ball when the board is at a certain angle? What are the forces on the ball? Can we find a cool equation that will match the ball rolling down the board?

All information and coding of these web pages copyright, Don Beaty, Creative Design