You Will Record Both Static and Kinetic (Sliding) Friction

Group Member Names:

Force of Friction Activity:

You will record both Static and Kinetic (Sliding) Friction

To record Static Friction- use measurement of Force just before before it starts moving!

To record Kinetic Friction use measurement of Force that it takes to pull object at a constant velocity!

PROCEDURES: For Rough Surface Measurement: 1) Have group member hold down felt on desk. 2) Have another group member hook up spring scale (force meter) to box and place box open end up onto felt 3) Pull on force meter and measure force of static friction (just before it moves) and kinetic friction (moving at constant velocity) 4) Record values into table on back.

For smooth surface measurement (no added mass): 1) Remove felt from desk and put back. You will use smooth desk surface for this one. 2) Have another group member hook up spring scale (force meter) to box and place box open end up onto felt 3) Pull on force meter and measure force of static friction (just before it moves) and kinetic friction (moving at constant velocity) 4) Record values into table on back.

For smooth surface measurement (100g mass added): 1) You will use smooth desk surface for this one. 2) Have another group member hook up spring scale (force meter) to box and place box open end up onto desk. Add 100g mass into box. 3) Pull on force meter and measure force of static friction (just before it moves) and kinetic friction (moving at constant velocity) 4) Record values into table on back.

For smooth surface measurement (500g mass added): 1) You will use smooth desk surface for this one. 2) Have another group member hook up spring scale (force meter) to box and place box open end up onto desk. Add 500g mass into box. 3) Pull on force meter and measure force of static friction (just before it moves) and kinetic friction (moving at constant velocity) 4) Record values into table on back. DATA TABLE:

Surface Type Mass Force of Static Force of Kinetic Friction (N) Friction (N) (just before moved) (moving with constant velocity) Rough No added mass

Smooth No added mass

Smooth 100g added

Smooth 500g added

QUESTIONS:

1. In general, do your results show the Static or Kinetic force of friction to be greater? (Give some data from table to support your conclusion)

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2. In general, do your results show that a smooth or rough surface creates a larger force of friction? (Give some data from table to support your conclusion)

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3. In general, what do your results show happens to the force of friction as mass increased? (Give some data from table to support your conclusion)

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