Basic Principle

When a magnet moves near a non-magneticconductor such as copper or aluminum, itexperiences dissipative force called Magneticbreaking

Magnetic breaking

Magnetic breaking force depends on the magneticfield strength, it is affected by the magneticmoment (µ), conductor conductivity (σc), the sizeend geometry of both magnet and conductor, thedistance between magnet and conductor (d) andmagnetic velocity (v) relative toward its conductor.

Empirically, Fpm can be stated as:

[N] (1)

With k0 is the constant depending on µ, σcconductor geometry of the permanent mademagnet in the experiment, d distance betweenmagnetic core and conductor surface [m], vmagnetic velocity [m/s], p and n exponent ialfactor which is determined within the experiment.

Peralatan1 Thick Doughnut Shaped Magnet tM = (6,3 ± 0,1). mm,diameter dM = (25,4 ± 0,1) mm2 Allumunium Bars1 Steep Plane With Track1 Plastic Support1 Stopwatch1 Ruler1 Thick Doughnut Shaped Magnet tM = (6,3 ± 0,1). mm,diameter dM = (25,4 ± 0,1) mm

Magnetic breakingLM 10

Fig 1. The magnetic south-north poles of a doughnutshape magnet.

Experiment objectives

To study Magnetic breaking force To determine factors which affects

Magnetic breaking force

Fig. 2 Steep plane and magnet set up

Experiment procedures

A. Experiment Preparation1. Clean up the steep plane so there is no debris!2. Arrange the steep plane as shown on Fig.2!3. Releases the magnets until it rolls and adjust

the angle on the steep plane so the object willnot move too quickly!

4. Place both aluminum bars as shown on Fig.3with a distance of about d=5mm! Rememberthe distance is measured from the magnetcenter

5. Release the magnet and let it roll. The magnetwill move slower due to magnetic breaking

B. Observation of magnetic breaking forceB.1. Dependency of force to velocityProcedures of the experiment is as shown onFig.2, with the distance of the magnet andconductor is around d=5mm (there is a 2mm gapbetween the magnet and conductor on each side).

1. Measure the variable needed to get a steepangle such as the height of the steep plane

2. Release the magnet so it rolls, wait until itreaches a terminal velocity (about 5cm fromabove), then measure the distance and timetaken to reach that speed.

3. Repeat steps with different heights

B.2.Dependency of force to distance

1. Choose an angle on the steep plane that isquite small. Measure tha variable of the steepplane to find the angle!

2. Measure distance d!3. Release the magnet so it rolls, wait until it

reaches a constant velocity (around 5cm fromabove), do a speed measurement!

4. On the same slope, try different varieties ofdistances between the magnet and conductoron both sides!

5. Repeat steps 3-4 several times

Data Analysis and Evaluation

1. Evaluate the equation of movement to reachterminal velocity so a relationship between thesteepness angle, speed, and the n factor isfound!

2. On experiment B.1. find the linear relationshipbetween velocity and n factor (possibly inlogarithm form), construct a graph of thatrelationship and do linier regression to find n (ddistance is constant)!

3. On experiment B.2. show the followingrelationship :

(2)

4. Do this linearization equation to findexponential factor p!

5. Analyze and give a conclusion to thisexperiment!

Fig 1. Steep plane and magnet setup