Mechanics > Newton's Laws > Applications > Friction

DCS# 1K20.10

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FRICTION BLOCK

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APPARATUS
 

laptop w/ LoggerPro and interface	206
motion detector, if desired	101-05-B1
force sensor	101-05-B2
1-kg wood block with hook	202-15-D
2 1-kg masses	202-04-F

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DESCRIPTION

Plot F vs. t while pulling the block with the force sensor to show that
1. the force of static friction can take on a range of values,
2. the maximum force of static friction is greater than the force of kinetic friction,
3. the force of kinetic friction is proportional to the normal force,
4. the force of kinetic friction is independent of area,
5. different surfaces have different coefficients of friction,
6. with display of v vs. t, the frictional force is independent of velocity. (This is less reliable, in part because it is difficult to maintain a constant force while pulling at higher speeds.)

NOTES

Zero the force sensor in the horizontal position before collecting data.
Make sure the force sensor number agrees with that of calibration file.
For a more dramatic difference between static and kinetic friction, drag the block along the angle of repose board (202-15-D) instead of the pasco track.