Question

pls send its answer its urgent

Answer 1

which answer do you need their are 4 questions ? please reply

Answer 2

Nature of surface (rough or smooth in contact):- No matter how smooth a surface look it has some irregular projections,but irregular surface have them in huge amount.For ex -roll a m ball on a plane surface (on a marble,etc)without applying a push to it .Measure the distance travelled by the ball.Now repeat this activity with that on a rough surface.You will some to know the difference