Friction (āĻā§°ā§āĻˇāĻŖ)
Definition (āĻ¸āĻāĻā§āĻāĻž)
Friction is a force that opposes motion between two surfaces in contact. : āĻā§°ā§āĻˇāĻŖ āĻšā§āĻā§ āĻāĻāĻž āĻŦāĻ˛ āĻ¯āĻŋāĻ¯āĻŧā§ āĻāĻ¤āĻŋā§° āĻŦāĻŋāĻĒā§°ā§āĻ¤ā§ āĻāĻžāĻŽ āĻā§°ā§, āĻ¯ā§āĻ¤āĻŋāĻ¯āĻŧāĻž āĻĻā§āĻāĻž āĻĒā§āĻˇā§āĻ āĻāĻā§ āĻāĻ¨ā§° āĻ˛āĻāĻ¤ āĻ¸āĻāĻ¸ā§āĻĒā§°ā§āĻļāĻ¤ āĻĨāĻžāĻā§āĨ¤
Key Points (āĻā§ā§°ā§āĻ¤ā§āĻŦāĻĒā§āĻ°ā§āĻŖ āĻ¤āĻĨā§āĻ¯)
- Friction always opposes motion : āĻā§°ā§āĻˇāĻŖ āĻ¸āĻĻāĻžāĻ¯āĻŧ āĻāĻ¤āĻŋā§° āĻŦāĻŋāĻĒā§°ā§āĻ¤ā§ āĻāĻžāĻŽ āĻā§°ā§
- It acts between surfaces in contact : āĻ āĻ¸āĻāĻ¸ā§āĻĒā§°ā§āĻļāĻ¤ āĻĨāĻāĻž āĻĒā§āĻˇā§āĻ āĻ¸āĻŽā§āĻšā§° āĻŽāĻžāĻāĻ¤ āĻāĻžāĻŽ āĻā§°ā§
- It can slow down or stop objects : āĻ āĻŦāĻ¸ā§āĻ¤ā§ā§° āĻāĻ¤āĻŋ āĻ§ā§ā§° āĻŦāĻž āĻŦāĻ¨ā§āĻ§ āĻā§°āĻŋāĻŦ āĻĒāĻžā§°ā§
Types of Friction (āĻā§°ā§āĻˇāĻŖā§° āĻĒā§ā§°āĻāĻžā§°) : Click Here
Factors Affecting Friction (āĻā§°ā§āĻˇāĻŖāĻ āĻĒā§ā§°āĻāĻžā§ąāĻŋāĻ¤ āĻā§°āĻž āĻāĻžā§°āĻ) : Click Here
MCQs : Exam Style
Q1. Friction is a: āĻā§°ā§āĻˇāĻŖ āĻāĻŋ ?
(a) Energy | (b) Force | (c) Motion | (d) Speed
Ans: (b) Force
Explanation: Friction is a type of force. āĻŦā§āĻ¯āĻžāĻā§āĻ¯āĻž: āĻā§°ā§āĻˇāĻŖ āĻāĻāĻž āĻŦāĻ˛āĨ¤
Q2. Friction acts between: āĻā§°ā§āĻˇāĻŖ āĻ’āĻ¤ āĻāĻžāĻŽ āĻā§°ā§ ?
(a) Air only | (b) Water only | (c) Two surfaces in contact | (d) Space
Ans: (c) Two surfaces in contact
Explanation: It occurs when surfaces touch. āĻŦā§āĻ¯āĻžāĻā§āĻ¯āĻž: āĻĒā§āĻˇā§āĻ āĻ¸āĻŽā§āĻš āĻ¸āĻāĻ¸ā§āĻĒā§°ā§āĻļāĻ¤ āĻĨāĻžāĻāĻŋāĻ˛ā§ āĻā§°ā§āĻˇāĻŖ āĻšāĻ¯āĻŧāĨ¤
Q3. Friction always: āĻā§°ā§āĻˇāĻŖ āĻ¸āĻĻāĻžāĻ¯āĻŧ -
(a) Helps motion | (b) Opposes motion | (c) Increases speed | (d) Stops gravity
Ans: (b) Opposes motion
Explanation: It works against motion. āĻŦā§āĻ¯āĻžāĻā§āĻ¯āĻž: āĻ āĻāĻ¤āĻŋā§° āĻŦāĻŋāĻĒā§°ā§āĻ¤ā§ āĻāĻžāĻŽ āĻā§°ā§āĨ¤
Q4. Friction can: āĻā§°ā§āĻˇāĻŖā§ āĻāĻŋ āĻā§°āĻŋāĻŦ āĻĒāĻžā§°ā§ ?
(a) Increase speed | (b) Stop objects | (c) Create light | (d) None
Ans: (b) Stop objects
Explanation: It slows down motion. āĻŦā§āĻ¯āĻžāĻā§āĻ¯āĻž: āĻ āĻāĻ¤āĻŋ āĻāĻŽāĻžāĻ āĻŦāĻž āĻŦāĻ¨ā§āĻ§ āĻā§°ā§āĨ¤
Q5. Which is an example of friction ? āĻā§°ā§āĻˇāĻŖā§° āĻāĻĻāĻžāĻšā§°āĻŖ āĻā§āĻ¨āĻā§ ?
(a) Falling of apple | (b) Walking on road | (c) Sunlight | (d) Sound
Ans: (b) Walking on road
Explanation: Friction helps us walk. āĻŦā§āĻ¯āĻžāĻā§āĻ¯āĻž: āĻāĻŽāĻŋ āĻā§°ā§āĻˇāĻŖā§° āĻŦāĻžāĻŦā§ āĻšāĻžāĻāĻāĻŋāĻŦ āĻĒāĻžā§°ā§āĨ¤
Short Answer (2–3 Marks)
Friction is a force that opposes motion between two surfaces in contact. It always acts opposite to the direction of motion and can slow down or stop moving objects.
āĻā§°ā§āĻˇāĻŖ āĻšā§āĻā§ āĻāĻāĻž āĻŦāĻ˛ āĻ¯āĻŋāĻ¯āĻŧā§ āĻĻā§āĻāĻž āĻ¸āĻāĻ¸ā§āĻĒā§°ā§āĻļāĻ¤ āĻĨāĻāĻž āĻĒā§āĻˇā§āĻ ā§° āĻŽāĻžāĻāĻ¤ āĻāĻ¤āĻŋā§° āĻŦāĻŋāĻĒā§°ā§āĻ¤ā§ āĻāĻžāĻŽ āĻā§°ā§āĨ¤ āĻ āĻ¸āĻĻāĻžāĻ¯āĻŧ āĻāĻ¤āĻŋā§° āĻŦāĻŋāĻĒā§°ā§āĻ¤ā§ āĻāĻžāĻŽ āĻā§°āĻŋ āĻŦāĻ¸ā§āĻ¤ā§ā§° āĻāĻ¤āĻŋ āĻāĻŽāĻžāĻ¯āĻŧ āĻŦāĻž āĻŦāĻ¨ā§āĻ§ āĻā§°ā§āĨ¤
Key Point:
Friction = Force that opposes motion : āĻā§°ā§āĻˇāĻŖ = āĻāĻ¤āĻŋā§° āĻŦāĻŋāĻĒā§°ā§āĻ¤ā§ āĻāĻžāĻŽ āĻā§°āĻž āĻŦāĻ˛