Friction

Question 1

What is Friction?

Answer 1

Friction is the force that opposes motion. Friction acts when two surfaces are in contact and acts in the opposite side of the moving object. It prevents things from moving or prevents stationery objects from moving.

Question 2

What does friction depend on?

Answer 2

Friction depends on nature of the surfaces in contact and depends on the mass of the moving object.

Question 3

which one will offer less friction? a smooth or a rough surface?

Answer 3

A smoother surface provides less friction compared to a rough surface, as in a rough surface the grooves and ridges get caught up with each other and thus slowing down the motion. On a smooth surface like ice it would be impossible to walk as it offers a smooth surface hence resulting in reduction of friction between our shoes and the ground.

Question 4

Advantages

Answer 4

1. would be impossible to walk. because of the friction between our shoes and the ground that provide us a surface to walk pushing our feet behind. impossible to walk on ice as it is a smooth surface.
2. Cars and buses able to move cause of the friction between the treaded tires and the roads.
3. brakes work cause of the friction applied which rub against the roads and wheels.
4. Causes nails and screws to hold on to walls.
5. we would not be able to light a matchstick without friction.
6. We would not be able to write on a paper without friction.

Question 5

What are slicks?

Answer 5

Slicks are the type of tires used in the racing cars to reduce friction which enables them to move faster.

Question 6

Disadvantgaes.

Answer 6

1. causes wastage of energy, ( Moving object has to overcome force of friction.)
2. wears out rubbing surfaces. ( soles of shoes wear out in few months. moving parts of machine.)
3. generates heat. (harmful. fast machine heat produced is high. arrangements have to be made to cool it down.)

Question 7

Polishing

Answer 7

it makes a rough surface smoother and reduces friction.

Question 8

Lubrication

Answer 8

lubricating surfaces with oil, grease or graphite. friction is between the thin lubrication layer which is much less. graphite used in the moving objects which produce high temperatures.

Question 9

Streamlining

Answer 9

fluids like water etc and air exert friction. frictional force that fluids exert is drag. friction is less in a streamlined body. ships have a streamlined body. birds, rockets, missiles are given a streamlined body too, to reduce friction.

Question 10

Rolling friction

Answer 10

rolling friction is less than sliding friction. this principle is used in ball bearings which contain steel balls or rollers. it is easier to roll an object then to slide it. this is the reason that vehicles and luggage are equipped with wheels.

Question 11

increasing friction.

Answer 11

used to avoid slipping. can be increased by making surfaces rough.

1. treaded tires and grooves on roads. prevents slipping on wet roads.
2. sand, gravel are scattered on wet roads to increase friction in rainy season. easier to walk.
3. spikes are offered in sports shoes to provide a better grip for athletes to increase friction.
4. Gymnasts use a coarse substance which gives them a firm grip.