Chapter 3 – Dynamics

Stretch out your palm and hold a book on it.

  • How much force you need to prevent the book from falling?

Ans.    Force equal to the weight of the book is needed to prevent the book from falling.

  • Which is action?

Ans.    Weight of the book is action in this case.

  • Is there any reaction? If yes, then what is its direction?

Ans.    Yes there is a reaction offered by hand. The direction of reaction is opposite to the weight.

  • Which shoe offer less friction?

Ans.    Shoe with flat sole will offer less friction

  • Which shoe is better for walking on dry track?

Ans.    On dry track, shoe with flat sole is batter for walking.

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  • Which shoe is better for jogging?

Ans.    Shoe which has not flat sole is batter for jogging.

  • Which sole will wear out early?

Ans.    Shoe with flat sole will wear out early.

  • Why is it easy to roll a cylindrical eraser on a paper sheet than to slide it?

Ans.    It is easy to roll a cylindrical eraser on a paper sheet than to slide it because rolling friction is less than sliding friction.

  • Do we roll or slide the eraser to remove the pencil work from our notebook?

Ans.    We slide the eraser to remove the pencil work from our notebook because we need more friction to remove the work and sliding friction is greater than rolling friction.

  • In which case do you need smaller force and why?

            (i) rolling                   (ii) sliding

Ans.    Rolling: Incase of rolling friction we need smaller force because there is contact with earth on only a single point.

            Sliding: Incase of sliding friction we need greater force because all the body is in contact with the earth.

  • In which case it is easy for the tyre to roll over?

            (i) rough ground       (ii) smooth ground

Ans.    Rough ground: Incase of rough ground it is difficult for the tyre to roll over because rough surface offer more friction.

            Smooth ground: Incase of smooth ground it is easier for the tyre to roll over because smooth surface offer less friction.
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This Post Has 45 Comments

  1. Muhammad Aziz

    I have need All chapter of physics MCQC

  2. Muhammad Nouman Tahir

    keep it up. we love you . May Allah blessed those who made this website and who is running this website

  3. Mrkhan

    Long questions es ma nahi hai

  4. syed muntazir

    thanks

  5. wadia

    boht km hen mcqs

    1. Author

      There are 60 mcqs in Extra MCQs Section. Check all the sections and wait for it to load.

  6. Ksko

    I like these notes.
    These are so good.

  7. Abdul hadi

    There are no short questions!!!!

    1. FARRUKH shehzad

      yes also send extra s.q

      1. Abdul hadi

        There are no short questions!!!!

  8. FARRUKH shehzad

    i want extra short question answers

  9. Khadija khan

    I also want some extra questions for board exams

  10. khadija khan

    plz add some extra questions for board exams 🙏

  11. Ayesha siddiqa

    plz add short queations

  12. Shama

    Please chapter may joh quick quiz hotayn han unn kay beh answer likh diya karayn

  13. LEGENDDANI

    I’m not totally satisfied

  14. fawad

    very good website

  15. fawad

    very good all ans are there

  16. Shamas dar

    😘😘😘😘😘👍👍👍👍💞💞💞SHABASH SHABASH SHABASH
    THANKS FOR YOUR HELP

    1. Manahil

      I do my preparation of board exam just from here …♥️♥️♥️♥️

  17. Sufian

    Thanks for 👉your help 😶😘😘😘😘

  18. ALI MALIK

    in exercise question/ answers questions from (3.18 to 3.20) is missing please add it

  19. Faiz Ajmal

    If vector A and B are added, under what condition their resultant magnitude is equal to A+B and under what condition their resultant is zero.
    Plzz answer it .Tomorrow is our board so i need its answer.

    1. Phishy

      I know I’m late but,
      The resultant of Vector A and B is equal to A+B , if both the vectors are in the same direction.
      Meanwhile, The resultant of A and B Vectors is equal zero, if both the vectors are in the opposite direction.

  20. Human

    These helped me alot. Jazakallah

  21. Phishy

    Very helpful. Jazakallah.
    Please do consider checking Ex Q.1 – MCQ no.8
    I believe the action force is on the Earth.
    The horse puts action force on the Earth, the Earth’s friction provide the Reaction force. Which allows the Horse to overcome the friction between the wheels of the cart and the Earth.
    (Horse + Earth) -> (Cart+Earth)
    So, the correct answer should be (b) option. (Earth)

    1. Fahad

      Yup
      I also thinks that

    2. legend

      yes u r right!

  22. zamad

    mention the formulas

  23. Muhammad Usman

    These notes are very helpfull indeed but there is a little mistake in QUESTION NO. 8 of long questions. in the mathematical derivation of friction, it is written that “” Friction is equal to the applied force that tends to move a body””.
    THE MISTAKE HERE IS THAT IF THE FRICTION IS EQUAL TO APPLIED FORCE, THE BODY WILL NEVER MOVE BECAUSE FRICTION OPPOSES MOTION.
    Kindly check it.

    1. Author

      ok, we’ll check it.

  24. Faizan Ahmed

    keep it up

  25. Jibran Imran Kayani

    Question 3.4 and 3.9 is much longer but you written in very short sentences and some of the answers is not related to the question. Please check for it.

    1. Organizer

      ok, we’ll check it.

  26. Jibran Imran Kayani

    MCQs are not related with the orignal Physics book class 9 Publisher: CARAVAN BOOK HOUSE, LAHORE

  27. Waseem Ali

    Add me in physics whatsapp group plz

  28. Ahmad

    I need physic all long question please any one help

  29. Hoor

    In back exercise questions last 3 questions are missing kindly check it.

    1. Author

      Ok, We’ll check it.

  30. Question mistakes

    Why there is a lot of mistakes in questions?

  31. hashim khan

    exercise last three questions are missing kindly check it

    1. Organizer

      ok, we’ll check it.

  32. Malik Irfan

    sir Please send me the physics chapter 3 and 6 notes

  33. Ahsan

    Dear sir there is mistake in (vii) mcqs
    It is kgms

    1. Organizer

      ok, we’ll check it.

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