This document discusses friction and the forces involved when objects touch or rub against each other. It explains that friction is the force that forms between surfaces in contact, like shoes and floors, kids and slides, hands rubbing together, and objects being pushed on the floor. Friction causes balls to slow down when they roll and objects like bicycles to be harder to move on rough surfaces like sand compared to smooth surfaces. Water and oil reduce the amount of friction between surfaces.

1. When you kick a ball, does it move
forever or it slows down and stops?

2. Why does it slow down and
stops?
When two surfaces touch each other or rub
each other, like the ball and the ground. It
produces a force called friction
The friction causes the object to slow
down.

3. What kind of force is formed between the
shoes and the floor when you are walking?
Friction force

4. What kind of force is formed between the
kids and the slide ?
Friction force

5. What kind of force is formed when you rub
your hands?
Friction force

6. What kind of force is formed when you try
to push any heavy object on the floor?
Friction force

7. Can you tell me where is the
friction formed in the following
pictures :

9. What happens when there is water on
the ground? Why?
Water reduces friction

10. What else reduces friction ?
Oil

11. Which is difficult to ride a
bicycle on, the floor or the sand?
Rough surface like sand, produces
more friction.

12. Which is easier to ride a bicycle on,
the floor or the grass
Smooth surfaces, produces less
friction.

13. Rough surfaces

14. Smooth surfaces

15. Force that happens between
objects that touch each other.

16. 1) Magnetism
2) Gravity
3) Friction
Which of these is a contact force?

17. Force that happens between
objects without touching each
other.

18. 1) Magnetism
2) Gravity
3) Friction
Which of these is a non-contact force?