Answer:

1.) Friction is a force that arises when things rub together. The frictional force between the road and tire is what allows the tire to "push" off the road, thus moving the car forward (Newton's third law — the action is the pushing frictional force, the reaction is the forward movement of the car).

2.) Friction occurs because no surface is perfectly smooth. Rougher surfaces have more friction between them. Heavier objects also have more friction because they press together with greater force. Friction produces heat because it causes the molecules on rubbing surfaces to move faster and have more energy.

3.)Friction is Undesirable: A friction is undesirable during ice skating or when a block is lifted or put down on the truck with the help of some inclined plane. If the friction is more between the block and inclined surface then a large force is required to push the block on the plane.

Explanation:

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Answer:

1. Why is walking and driving a car friction?

They are friction because the friction makes these movements possible.  

2. Why is there friction?

I think there is friction because without friction, there will be no movement and if there is, it will be unstoppable.

3. 2 examples of undesirable effects of friction​

1st Ex. When pushing a huge cabinet, the friction makes the cabinet harder to push.

2nd Ex. When walking or running carelessly, the friction can make us fall and hurt ourselves.

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