(a) Given examples to show that firction depends on the nature of two surfaces in contact.
(b) Give an example to show that friction depends on the force with which the two surfaces are pressed together.
(a) Given examples to show that firction depends on the nature of two surfaces in contact.
(b) Give an example to show that friction depends on the force with which the two surfaces are pressed together.
a-To see the effect of friction on different surfaces.
1 Take a sheet of paper, a handkerchief, a hand towel, a rectangular piece of glass and wood as surfaces and a pencil.
2 Now roll the pencil on each surface.
3 Number the surfaces in the order in which the pencil rolled easily on them. Also, mention whether the surface is rough or smooth.
What do you observe ?
You will observe that pencil rolls most easily on the smoothest surface.
b-
Example.
When we gently push a book on a table, it stops after moving for some distance because friction opposes relative motion between the surfaces of the book and the table
Now place a weight on the book. If we push the book , it moves lesser distance than before. So it depends on the force with which both the surfaces are pressed together
a-To see the effect of friction on different surfaces.
1 Take a sheet of paper, a handkerchief, a hand towel, a rectangular piece of glass and wood as surfaces and a pencil.
2 Now roll the pencil on each surface.
3 Number the surfaces in the order in which the pencil rolled easily on them. Also, mention whether the surface is rough or smooth.
What do you observe ?
You will observe that pencil rolls most easily on the smoothest surface.
b-
Example.
When we gently push a book on a table, it stops after moving for some distance because friction opposes relative motion between the surfaces of the book and the table
Now place a weight on the book. If we push the book , it moves lesser distance than before. So it depends on the force with which both the surfaces are pressed together
