Lab 14
Purpose: Look at a two-dimensional collision and determine if momentum and energy are conserved.
To prove momentum and energy are conserved in two dimensional,I need to set up the equipment and use experiment result to prove them.
This is the set up looks like.
Why using this equipment is that this set up can capture the process of the two ball hit each other in two dimensional.
(Make sure that the glass surface is leveled.)
Connecting the camera to the computer with logPro.
By using a steel ball to hit another steel ball with same weight and aluminum ball. then using the camera to capture the process the balls collision.
Because it's two dimensional, need to show that it's conserved at x and y two dimensional.
I am trying to show is that by using the collision to prove that energy and momentum are conserved.
After I capture the process of two ball hit each other and split, I used the logger Pro point the position the balls are and set up the origin where they hit.
this is how you set up the point with the process, set up the steel ball as x axis, and where they hit as origin.
Add point Series to make it two dimensional.
Then Capture and Saving the two process of the steel ball hit another steel ball and aluminum ball. Do the point work on the process and get the picture.
This is the picture after
The first one is steel with steel, and second one is steel and aluminum ball.
In the picture,
X2, Y2 are the steel ball with velocity to hit another ball.
X, Y are steel ball and aluminum ball at rest first.
X2 represent steel ball one's on the x axis velocity which are two different velocity, and Vx is before collision and V'x is after.
Y2 represent steel ball one's on the y axis velocity which are two different velocity, and Vy is before collision and V'y is after.
X represent rest steel ball one's on the x axis velocity which are two different velocity, and Vx is before collision and V'x is after.
Y represent rest steel ball one's on the y axis velocity which are two different velocity, and Vy is before collision and V'y is after.
This is the first data when steel ball hit another steel ball.
We can see that Px very close to P2x only 5.1% off, and Py very close P2y too only . that's can tell that momentum is conserved in two dimensional.
Second calculation is checking the energy by using Ki = Kf.
they are very close to almost same, so can say energy is conserved in two dimensional.
This is the second data when steel ball hit aluminum ball.
We can see that Px very close to P2x, and Py very close P2y too. that's can tell that momentum is conserved in two dimensional.
Second calculation is checking the energy by using Ki = Kf.
they are very close to almost same, so can say energy is conserved in two dimensional.
Why using this equipment is that this set up can capture the process of the two ball hit each other in two dimensional.
(Make sure that the glass surface is leveled.)
Connecting the camera to the computer with logPro.
By using a steel ball to hit another steel ball with same weight and aluminum ball. then using the camera to capture the process the balls collision.
Because it's two dimensional, need to show that it's conserved at x and y two dimensional.
I am trying to show is that by using the collision to prove that energy and momentum are conserved.
After I capture the process of two ball hit each other and split, I used the logger Pro point the position the balls are and set up the origin where they hit.
this is how you set up the point with the process, set up the steel ball as x axis, and where they hit as origin.
Add point Series to make it two dimensional.
Then Capture and Saving the two process of the steel ball hit another steel ball and aluminum ball. Do the point work on the process and get the picture.
This is the picture after
In the picture,
X2, Y2 are the steel ball with velocity to hit another ball.
X, Y are steel ball and aluminum ball at rest first.
X2 represent steel ball one's on the x axis velocity which are two different velocity, and Vx is before collision and V'x is after.
Y2 represent steel ball one's on the y axis velocity which are two different velocity, and Vy is before collision and V'y is after.
X represent rest steel ball one's on the x axis velocity which are two different velocity, and Vx is before collision and V'x is after.
Y represent rest steel ball one's on the y axis velocity which are two different velocity, and Vy is before collision and V'y is after.
And it's the time to do the calculation to prove the momentum and energy conserved.
So I need to show that the energy before is same as the energy after, and the moment before is also same as after; if both are true, I can say they are conserved in two dimensional.
So I need to show that the energy before is same as the energy after, and the moment before is also same as after; if both are true, I can say they are conserved in two dimensional.
This is the first data when steel ball hit another steel ball.
We can see that Px very close to P2x only 5.1% off, and Py very close P2y too only . that's can tell that momentum is conserved in two dimensional.
Second calculation is checking the energy by using Ki = Kf.
they are very close to almost same, so can say energy is conserved in two dimensional.
We can see that Px very close to P2x, and Py very close P2y too. that's can tell that momentum is conserved in two dimensional.
Second calculation is checking the energy by using Ki = Kf.
they are very close to almost same, so can say energy is conserved in two dimensional.
Conclusion
As showing there, with this experiment just show that even in two dimension collision; we can tell that momentum and energy are conserved. Even though it's not exactly same but very close, and the reason may cause uncertainty and errors would be friction on the table may lose energy, point on process is not accurate , or mistake made operator when doing the experiment. However, according to the results those errors and uncertainty are not big and acceptable.
This is all pretty clear. Nicely done. You could add in your procedure that you are carrying out the collision of the two balls on a glass surface that you leveled.
回复删除I wish you would show your numbers plugged into your equations. You list values, you list equations, and you list results. If you made a mistake somewhere plugging in your numbers, I wouldn't be able to tell. The syllabus is pretty clear on what this should look like.
Generally speaking, KE is NOT conserved in a real collision. We aren't trying to prove that KE is conserved. We are trying to tell IF it is conserved.
It is a little odd that you measured the masses of your balls to only +/- 10 grams.
回复删除We had balances in the lab that measured to a tenth of a gram, so you should be able to report masses like 0.0213 g rather than 0.02 g. Your results look close, but there is so much uncertainty in your reported masses that it is hard to tell.