Question

conduct an experiment to find out the effect of roughness on frictional force

Answer 1

On a rough surface for eg. a road place a rough wooden block , now try to push it. You will notice that the block take your extra energy to be get pushed
why do it happens?
it happens because of the frictional force which is present on both the surfaces .
that is the interlock between the two bodies . This is call friction. ....
Hope this answer help you :-)

Answer 2

Frictional Force:

Frictional force refers force generated by "two surfaces" that 'contacts' and 'slide' against each other. These forces are mainly affected by the "surface texture" and "amount of force" impelling them together.

Effect of roughness on frictional force:

• Choose three surfaces with different levels of roughness.
• Roll a ball along these surfaces.
• Record the time taken for the ball to come to rest and also the distance travelled by the ball.
• From the recorded data, we will notice that value of speed drops with increase in roughness.
• This is due to the fact that friction increases with increase in roughness.