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Force and Laws of Motion

Each subtopic includes About section, revision page link, 10 preview questions, and practice CTAs.

Balanced and Unbalanced Forces

Subtopic

Balanced and Unbalanced Forces under Force and Laws of Motion for Grade 9 CBSE.

About Topic & Revision

Preview questions (no answers)

  1. 1.

    If the net force on an object is directed towards the North, the object will accelerate towards the:

    A.

    South

    B.

    East

    C.

    West

    D.

    North

  2. 2.

    A book placed on a horizontal table is acted upon by two forces: weight and normal force. If the book is at rest, these forces are:

    A.

    Unbalanced

    B.

    Acting in the same direction

    C.

    Balanced

    D.

    Unequal in magnitude

  3. 3.

    If you push a toy car and it moves faster and faster, you are applying:

    A.

    A balanced force

    B.

    An unbalanced force

    C.

    No force

    D.

    A force equal to friction

Download the worksheet for Force and Laws of Motion - Balanced and Unbalanced Forces to practice offline. It includes additional chapter-level practice questions.

First Law of Motion (Inertia)

Subtopic

First Law of Motion (Inertia) under Force and Laws of Motion for Grade 9 CBSE.

About Topic & Revision

Preview questions (no answers)

  1. 1.

    Galileo used which of the following to demonstrate the concept of inertia?

    A.

    Magnets

    B.

    Inclined planes

    C.

    Pendulums

    D.

    Spring balances

  2. 2.

    If we apply a force of 0 N0\text{ N} to an object of mass 5 kg5\text{ kg} that is already at rest, the object will:

    A.

    Move with constant speed

    B.

    Remain at rest

    C.

    Accelerate

    D.

    Move in a circle

  3. 3.

    When a branch of a tree is shaken, some leaves fall off. This is due to:

    A.

    Inertia of rest of the leaves

    B.

    Inertia of motion of the leaves

    C.

    Acceleration of the leaves

    D.

    Force of gravity only

Download the worksheet for Force and Laws of Motion - First Law of Motion (Inertia) to practice offline. It includes additional chapter-level practice questions.

Second Law of Motion (Momentum)

Subtopic

Second Law of Motion (Momentum) under Force and Laws of Motion for Grade 9 CBSE.

About Topic & Revision

Preview questions (no answers)

  1. 1.

    What is the momentum of a 0.5 kg0.5\text{ kg} ball moving at 10 m/s10\text{ m/s}?

    A.

    50 kg⋅m/s50\text{ kg}\cdot\text{m/s}

    B.

    5 kg⋅m/s5\text{ kg}\cdot\text{m/s}

    C.

    0.05 kg⋅m/s0.05\text{ kg}\cdot\text{m/s}

    D.

    20 kg⋅m/s20\text{ kg}\cdot\text{m/s}

  2. 2.

    The total momentum of an isolated system remains constant. This is the Law of:

    A.

    Conservation of Energy

    B.

    Conservation of Momentum

    C.

    Inertia

    D.

    Gravity

  3. 3.

    An object of mass 2 kg2\text{ kg} moving at 10 m/s10\text{ m/s} has the same momentum as an object of mass 4 kg4\text{ kg} moving at:

    A.

    2.5 m/s2.5\text{ m/s}

    B.

    5 m/s5\text{ m/s}

    C.

    20 m/s20\text{ m/s}

    D.

    40 m/s40\text{ m/s}

Download the worksheet for Force and Laws of Motion - Second Law of Motion (Momentum) to practice offline. It includes additional chapter-level practice questions.

Third Law of Motion

Subtopic

Third Law of Motion under Force and Laws of Motion for Grade 9 CBSE.

About Topic & Revision

Preview questions (no answers)

  1. 1.

    The total momentum of two objects before a collision is equal to the total momentum after the collision if no external force acts. This is linked to which law?

    A.

    Newton's First Law

    B.

    Newton's Second Law

    C.

    Newton's Third Law

    D.

    Both Second and Third Laws

  2. 2.

    While rowing a boat, the rower pushes the water backwards. This is the:

    A.

    Action force

    B.

    Reaction force

    C.

    Balanced force

    D.

    Inertial force

  3. 3.

    If the action force is F12F_{12} and reaction force is F21F_{21}, then which is true?

    A.

    F12=F21F_{12} = F_{21}

    B.

    F12=−F21F_{12} = -F_{21}

    C.

    F12>F21F_{12} > F_{21}

    D.

    F12<F21F_{12} < F_{21}

Download the worksheet for Force and Laws of Motion - Third Law of Motion to practice offline. It includes additional chapter-level practice questions.

Force and Laws of Motion - Class 9 Science (CBSE) | Krit.club