GyansetuVidya ka pul
CHAPTER 08

Force and Laws of Motion

Overview

Motion ka matlab hai object ki position samay ke saath badalna. Is chapter mein distance aur displacement ka farak, speed aur velocity, acceleration, aur motion ke teen equations seekhoge — saath mein distance-time aur velocity-time graphs padhna bhi. Yeh physics ka base chapter hai — aage ke saare mechanics isi par khada hai.

Key Concepts

  • 01Distance wo total path hai jo object ne travel kiya (scalar); displacement initial se final position ka seedha gap hai (vector).
  • 02Uniform motion: equal time intervals mein equal distance. Non-uniform: barabar nahi.
  • 03Speed scalar hai (distance/time); velocity vector hai (displacement/time) — direction ke saath.
  • 04Acceleration velocity ki change-of-rate hai — a = (v − u)/t; SI unit m/s².
  • 05Velocity-time graph ka slope acceleration batata hai; graph ke neeche ka area distance batata hai.
  • 06Teen equations of motion uniform acceleration ke liye hain — teeno ko derivation se bhi aana chahiye (graphical).

Important Formulas

Acceleration: a = (v − u)/t
First equation: v = u + at
Second equation: s = ut + ½at²
Third equation: v² = u² + 2as
Average speed = total distance / total time

Practice Questions

  1. 01Ek car 10 m/s se chal rahi thi, 5 s mein 20 m/s ho gayi — acceleration nikalo.
  2. 02Ek object rest se 4 m/s² acceleration se 10 s chala — distance kitna cover hua?
  3. 03Ek body ka velocity-time graph ek seedhi line hai (slope positive) — body ka motion kaisa hai?
  4. 04Ek runner circular track ke ek chakkar 200 m mein 40 s mein poora karta hai — displacement kitna?
  5. 05Ek stone ko upar pheko — sabse upar par uska acceleration kitna hoga? (g = 9.8 m/s²)
Summary

Motion ka study position change se shuru hota hai. Distance scalar, displacement vector. Speed/velocity aur acceleration ke saath teen equations of motion (v = u + at, s = ut + ½at², v² = u² + 2as) se koi bhi uniform-acceleration problem solve ho jaata hai. Graphs se bhi answers nikalte hain: slope = acceleration, area = distance.

Handwritten notes
Handwritten — class notes
Handwritten — class notes
Diagrams + workings
Diagrams + workings

Chapter-end quiz

5 MCQs

Option tap karo — turant pata chalega sahi ya galat, explanation ke saath.

  1. Q1.Acceleration ka SI unit kya hai?

  2. Q2.Distance aur displacement mein kya farak hai?

  3. Q3.Velocity-time graph ka slope kya batata hai?

  4. Q4.Pehli equation of motion kaunsi hai?

  5. Q5.Uniform motion mein object kya karta hai?

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