Lab 3 Acceleration of Gravity on an Inclined Plane

In this lab we attempted to find the acceleration of gravity on an object. We started with a frictionless track, a car for the track, a couple blocks of wood (to shift incline), and a device that measured position vs time. We connected this device to a computer and had a program draw us graphs of position vs time and plot its velocity versus time as well.

 The picture above shows roughly all the equipments needed to do this lab.

From there we inclined the track at an angle of 2.40 degrees above the horizontal(note error). We did this by measuring the height on both sides of the track and using the pythagrean theorem  We took many trials until we got the best three possible results. The computer program had a property that gave us a linear fit. We used the linear fit on two parts of the velocity graph in order to get an average acceleration reading.

 

 

After we had three reasonable trials for the first heigh (angle), we changed the hieght of the track again. This time we raised one side a bit higher and developed an angle 4.69 degrees above the horizontal. We did a few more trials until we got the desired graphs we were looking for.

 We were given an equation for gravity. The equation stated, the average acceleration divided by sine of the angle theta would give us acceleration due to gravity. The percent error was calculated by subtracting the final answer from the actual gravity, taking the magnitude of that value, and dividing it by the actual value and multiplying it by 100.

	Height	Length	Angle	Accel 1	Accel 2	Avg Accel	Gravity	% Error
One	9.55 cm	228 cm	2.4	.4021 m/s/s	.3205 m/s/s	.3613 m/s/s	8.62 m/s/s	12.1
Two	9.55 cm	228 cm	2.4	.3921 m/s/s	.3186 m/s/s	.3554 m/s/s	8.49 m/s/s	13.5
Three	9.55 cm	228 cm	2.4	.4000 m/s/s	.3135 m/s/s	.3568 m/s/s	8.52 m/s/s	13.2
Four	18.65 cm	228 cm	4.69	.7903 m/s/s	.6956 m/s/s	.7430 m/s/s	9.09 m/s/s	7.38
Five	18.65 cm	228 cm	4.69	.8077 m/s/s	.7118 m/s/s	.7598 m/s/s	9.29 m/s/s	5.28
Six	18.65 cm	228 cm	4.69	.7959 m/s/s	.7100 m/s/s	.7530 m/s/s	9.21 m/s/s	6.13

In conclusion we found that sin theta times gravity gave us the acceleration of the car. It was very interesting that the lab proved the books point. The reasons we didn't come too close to the reading seemed, for one, was lack of track space. It seems as though the track cars that were at a higher angle came closer to the actual value of gravity because it moved faster, over coming and negligable force of friction on the track. Other than that the hieght measurements with the meter stick could throw off the reading a bit. The unlevel surfaces of the table could interfere with our readings. I'm still very curious to know why on the steeper incline we were more accurate. I was pleased to see all readings were very precise, shows that we were doing the experiment correctly.