Title: Conservation of Energy Lab Purpose: To verify that the total energy of an object doesn't change if the object hasn't done work.

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Title: Conservation of Energy Lab

Purpose: To verify that the total energy of an object doesn't change if the object hasn't done work.

Procedure:

1. Attach a photo gate to the bottom of the tube that is attached to a vertical metal rod.

2. Attach the photo gate to the computer, and open Mac Motion.

3. Record all measurements, tube to ground, tube to photo gate.

4. Go get a small piece of PVC pipe that will be dropped through the tube

5. Measure both mass and length of the small piece of PVC pipe.

6. Drop the small piece of PVC pipe through the long piece of pipe and through the photo gate

7. Record the amount of time it took for the small piece of PVC pipe to pass by the photo gate.

Data:

pg = photo gate

Small piece of PVC pipe mass: .0116kg

Small piece of PVC pipe length: .058m

Length from the top of the tube to the ground = 1.867m

Distance from the photo gate to the ground. = .266 m

Trial #Time for the object to pass through the (pg)

1.0115s

2.0116s

3.0118s

Calculations:

TE = Total Energy

PE = Potential Energy

KE = Kinetic Energy

m = mass

g = gravity = 9.81N/kg

h = height

Calculating the TE of the small piece of PVC pipe at the top of the tube before we dropped it.

PE=mgh=(.0116kg)(9.81N/kg)(1.876m)=0.212J

KE=1/2mv"=0J

TE=PE+KE=0.212J+0J=0.212J

Calculating the Average Speed of the object as it passes through the photo gate.

.0115s+.0116s+.0118s

------------------------------- = .0116s

3

.058m/.0116s

------------------- = 5m/s

.0116

Calculating the TE of the small piece of PVC pipe as it passes through the photo gate.

PE=mgh=(.0116kg)(9.81N/kg)(.266m)=0.030J

KE=1/2mv"=1/2(.0116kg)(5m/s)"=0.145J

TE=PE+KE=0.175J

Calculating the difference in TE between the top of the tube and the photo gate

.212J-.175J=.037J

.175J

-------- = 83%

.212J

100%-83%=17%

This shows that we incurred a loss of 17% of the TE between the drop of the small piece of PVC pipe and it passing through the photo gate.

Conclusions/Sources of Error

We found that the experiment was not perfect but the formula does seem to be accurate. Our groups experiment showed a 17% loss in energy between our original total energy calculation at the top of the tube and our total energy calculation as the object passed through the photo gate. This loss in energy can be accounted for by friction between the small piece of PVC pipe and the inner wall of the large pipe, as well as the impact of air molecules on the small piece of PVC pipe.

Sources of error for this experiment mostly come in the form of setup; if our large PVC pipe was at a small angle it would have increased friction and decreased the total energy of the small piece of PVC pipe as it passed through the photo gate.