friction force

friction force

L1.3

What is friction?

Friction is a force that slows down moving objects

Multiple Choice

Friction is a force that acts in an ___________ direction of movement.

• similar

• opposite

• parallel

• west

Multiple Choice

THE FRICTION FORCE IS A CONTACT FORCE.

• TRUE

• FALSE

 why there is friction?

all surfaces, even surfaces that feel very smooth, are uneven.

Multiple Choice

The rougher the surface, the faster an object will travel over the surface.

• True

• False

Reducing friction

People often try and reduce friction, for example, (lubrication)

-skiers wax the bottoms of their skis to reduce friction and make them go faster.

- Cyclists put oil on the axles of their bicycles to reduce friction. This is called lubrication. A layer of oil between two surfaces makes it easier for the surfaces to slide over each other. It reduces the force of friction.

Multiple Choice

----------- is applied to the moving parts of a vehicle to reduce friction.

• water

• grease

• powder

Multiple Choice

Oil and grease are

• powder

• lubricants

• paste

There are ball-bearings inside the wheels of a skateboard. They roll over each other as the wheel turns, and reduce friction.

Friction can be useful

- When you walk friction is useful. Friction acts between your feet and the ground, making it possible for you to move.

-Vehicles also need the force of friction between the tires and the road to make them move

Bicycles and cars also need friction to stop. The force of friction acts between their brakes and the wheels.

Multiple Choice

We are able to walk because of friction between the ---------- and the ground

• force

• feet

• pull

• push

Multiple Choice

we can walk on a wet floor easily

• true

• false

Multiple Choice

Q4. Which is not the advantage of friction?

• Friction helps in walking.

• Friction allows us to write on paper.

• Cars and buses move safely on roads due to friction.

• Friction causes wear and tear.

Multiple Choice

What does friction produce?

• light
• sound
• heat
• gravity

Multiple Choice

USES OF FRICTION?

• WE CAN EAT

• WE CAN THINK

• WE CAN WRITE

Multiple Choice

Q4. Which is not the advantage of friction?

• Friction helps in walking.

• Friction allows us to write on paper.

• Cars and buses move safely on roads due to friction.

• Friction causes wear and tear.

what we learned today !!!!

• Friction is useful for grip, to start moving, or for braking.

• The force of friction slows things down.

• friction is not a bad thing

• and more !!!!!

pg 13

1 What causes the force of friction between two surfaces that are sliding over each other?

2 Explain how using oil for lubrication reduces friction.

3 a There is a thin layer of water between the blade and the ice. Suggest how this affects friction and helps the skater. b Suggest why ice skates have a jagged edge at the front.

4 Tyres have treads to remove water from between the tyre and the road. Why is it important to remove the water?