Lab #13: Magnetic Potential Energy Lab
Dahlia - Ariel - Carlos
10-Oct-2016
The purpose of the lab#12 is to verify that conservation of energy is applied to the specific system in the lab.
I. Set up:
A friction-less cart with a strong magnet on one end approaches a fixed magnet of the same polarity.
When the cart is at the position of closet approach to the fixed magnet, the carts KE is momentarily zero and all of the emery in the system is stored in the magnetic field as magnetic potential energy, transformed back to KE.
However, the problem was I did not know the formula of magnetic potential energy, thus, I had to figured out how to to calculate the value of magnetic potential energy.
II. Calculate magnetic potential energy:
When looking at example from gravity, and proved it, I could conclude that
energy = - integral of force in environment.
So, to calculate the magnetic energy, I just needed to figure out the force of magnet, then integral it to have the magnetic potential energy.
To find the force of magnet, I used a glider on an air track. If I raise one end of the air track, the cart will end up at some equilibrium position, where the magnetic repulsion force between the two magnets will equal the gravitational force component on the cart paralleled to the track.
From this, I had data
From FBD, I had F=Mgsin(angle)
with M=0.338 kg
g=9.8ms^2
I had graph of F vs. r
The curve fit of this data was the force of magnet.
When I had magnetic force, I could easily to find magnetic potential energy by integral the magnetic force.
III. Verify conservation of energy
Now, I used a motion sensor to record the position and velocity of the cart
However, the position which motion sensor record was not the distance between 2 magnets, Thus I had to find the separation, the distance between 2 magnets
In theory, the graph of energy vs position and energy vs. time of kinetic energy and magnetic energy had to come out:
with KE= 1/2 m v^2
ME= -integral of magnetic force
I came out with graph:
with data
From the graph, I could realize that the sum of KE and ME was conservative. the line of the sum had a negative slope because the energy lost during friction.
I. Set up:
A friction-less cart with a strong magnet on one end approaches a fixed magnet of the same polarity.
When the cart is at the position of closet approach to the fixed magnet, the carts KE is momentarily zero and all of the emery in the system is stored in the magnetic field as magnetic potential energy, transformed back to KE.
However, the problem was I did not know the formula of magnetic potential energy, thus, I had to figured out how to to calculate the value of magnetic potential energy.
II. Calculate magnetic potential energy:
energy = - integral of force in environment.
So, to calculate the magnetic energy, I just needed to figure out the force of magnet, then integral it to have the magnetic potential energy.
To find the force of magnet, I used a glider on an air track. If I raise one end of the air track, the cart will end up at some equilibrium position, where the magnetic repulsion force between the two magnets will equal the gravitational force component on the cart paralleled to the track.
R was the distance between 2 magnets.
From this, I had data
with M=0.338 kg
g=9.8ms^2
I had graph of F vs. r
When I had magnetic force, I could easily to find magnetic potential energy by integral the magnetic force.
III. Verify conservation of energy
Now, I used a motion sensor to record the position and velocity of the cart
ME= -integral of magnetic force
I came out with graph:
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