Give an example to show that friction depends on the force with which the two surfaces are pressed together.
Answers
When we gently push abook on a table,it stops after moving for some distance because friction opposes relative motion between the surfaces of the book and the table If we apply the force along the right direction,the friction acts along that direction in both cases,the force opposes the motion of the book.
I hope you will observe this statement.
OK...
Answer:
suppose we have two boxes of the same size but one box is light and the other box is heavy. If we push both the boxes on the floor, one by one, we will find that we have to apply only a small force to make the lighter box move on the floor but a much larger force has to be applied to make the heavier box move on the floor. This shows that there is less friction between the light box and floor but much more friction between the heavy box and the floor. since the surfaces of heavy box and floor are pressed together harder (with a greater force) the friction between them increases and becomes much greater. This greater friction does not allow the heavy box to be moved on floor by applying a small force. A much larger force of our push has to be applied to make the heavy box move on the floor.