A piece of carpet is pulled using two scales whose readings, when added, give the total frictional force.

Newton's First Law, Second Law, Friction Last Updated: Jan 13th, 2015

1. To show that frictional force is independent of area of contact. 2. To make use of the F=uR relationship in a demonstration of friction.

- Large piece of carpet - Two scales with rope - A known weight

- Using a known weight, do a preliminary experiment to determine the coefficient of friction (u) between the carpet and the table. - With one student sitting on the carpet, have two others drag the carpet and student. With the carpet just moving, read the two scales and add their readings. - The same total reading should be obtained when the student is asked to lie down on the carpet and the experiment repeated. - Using the pre-determined value for u, the student's weight can now be calculated using R=F/u. - A final experiment can be done using the other side of the carpet to show a different F value and hence a different coefficient of friction.