This presentation is helpful for students to understand the concept of force and contact and non contact forces in ICSE physics class IX

1. CONTACT &
NON CONTACT
FORCES

2. What is Force?
• The Force is an external cause which changes or tends
to change the state of rest or uniform motion of a body
in straight line.
• A force may act in form of PUSH or PULL

3. Balanced & Unbalanced Forces
Balanced Force Unbalanced Force
When two forces are equal in
magnitude but opposite in
direction acting on the same
body, we get the net forces
acting on a body equal to Zero.
When two forces are unequal in
magnitude but opposite in
direction acting on the same
body, we get the net forces
acting on a body unequal and
non-zero.
Balanced forces do not change
the state of rest or uniform
motion of the body.
Unbalanced force makes the
body to
Start or stop moving
Accelerate / decelerate
Change the direction / shape of
body

4. Balanced & Unbalanced Forces

5. Effects of Force
• Move a stationary object
• Stop a moving object
• Accelerate / decelerate a moving object
• Change the direction of a moving object
• Change the shape of an object
• Change the size of an object

6. Move a stationary object
Hitting a golf ball by a club Pushing a table
Pulling a box Kicking a stationary football

7. Stop a moving object
Fielder stoping a cricket ball Brakes applied to a moving car
Stoping a football by Goal Keeper Moving ball stops due to friction

8. Accelerate / decelerate a moving
object
Pushing a bicycle Pulling a bicycle
Juggling of balls Player hitting a baseball using bat

9. Change the direction of a moving
object
Football Player kicking the ball Trajectory of a stone
Batsman hitting the ball Striking the carrom Coins

10. Change the shape of an object
Squeezing of tooth paste Clay moulding by hands
Hitting the Dough Hitting the hot iron with hammer

11. Change the size of an object
Compressing the spring Squeezing of sponge
Blowing air into balloon Stretching the rubber band

12. Types of Forces
• Contact Force: The Forces which acts directly
through a contactor are called Contact Forces.
• Non-Contact Force: The Forces which acts
without any contactor are called as Non Contact
Forces.

13. Contact Forces
• Friction Force
• Normal Reaction Force
• Tension Force
• Collision Force

17. A collision is the event in which two or more bodies
exert forces on each other in about a relatively short
time. Although the most common use of the
word collision refers to incidents in which two or more
objects collide with great force, the scientific use of the
term implies nothing about the magnitude of the force
Collision Force

18. Non - Contact Forces
• Gravitational Force
• Magnetic Force
• Electric Force