Module 4: Momentum, Impulse and Collisions Notes Kannur University KU1DSCPHY101 | BSc Physics Kannur University Notes

 Access detailed Kannur University KU1DSCPHY101 Physics notes for Module 4: Momentum, Impulse, and Collisions, prepared as per the FYUGP Semester 1 syllabus approved in 2025. This comprehensive guide explains core concepts such as linear momentum, impulse-momentum theorem, elastic and inelastic collisions, and conservation laws in a clear, exam-focused manner. Ideal for BSc Physics students under Kannur University’s New Education Policy (NEP) 2020-aligned FYUGP framework, these notes provide conceptual clarity, derivations, solved problems, and key formulas. Whether preparing for internal exams, assignments, or end-semester evaluations, this material strengthens your understanding of fundamental mechanics. Covers real-life applications and problem-solving strategies to help you excel in physics. Suitable for students, tutors, and educators looking for quality, syllabus-aligned content. Download or read online to master Momentum and Collisions in Mechanics with ease. Stay ahead with the best Kannur University Physics study resources.

Topics Covered

• Momentum and Impulse, Newton’s Second Law in terms of Momentum, The Impulse- Momentum Theorem, Momentum and Kinetic Energy Compared, Conservation of Momentum
• Momentum Conservation and Collisions, Elastic and Inelastic Collisions, Completely Inelastic Collisions, Center of Mass, Rocket Propulsion
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• From the textbook: University Physics with Modern Physics – Hugh D Young & Roger A Freedman-14th edition, 2016.

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COMPLETE NOTES FOR SEMESTER 1 HAS BEEN POSTED IN THIS WEBSITE

Module 1: Notes Module 1: Newton’s Laws of Motion Kannur University Notes KU1DSCPHY101

Module 2: Notes Module 2 & 3: Work and Kinetic Energy, Potential Energy and Energy Conservation Kannur University Notes KU1DSCPHY101

Module 3: Notes Module 2 & 3: Work and Kinetic Energy, Potential Energy and Energy Conservation Kannur University Notes KU1DSCPHY101

Module 4: Notes Module 4 : Momentum, Impulse and Collisions Notes Kannur University KU1DSCPHY101

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MOMENTUM

• Definition: Measure of motion, vector quantity.

  $$\vec{p} = m\vec{v}$$

• Unit: kg·m/s.

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NEWTON’S SECOND LAW IN TERMS OF MOMENTUM

• General form:

  $$\vec{F}_{\text{net}} = \frac{d\vec{p}}{dt}$$

• For constant mass: reduces to $F = ma$.

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IMPULSE

• Definition: Product of force & time interval.

  $$\vec{J} = \vec{F} \Delta t$$

• Unit: N·s (same as momentum).

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IMPULSE–MOMENTUM THEOREM

• Net impulse on a body = change in momentum:

  $$\vec{J} = \Delta \vec{p}$$

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MOMENTUM VS. KINETIC ENERGY

• Momentum: vector, $p = mv$.

• Kinetic Energy: scalar, $KE = \frac12 mv^2$.

• A body with momentum always has KE, but same momentum doesn’t mean same KE (depends on mass).

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CONSERVATION OF MOMENTUM

• In an isolated system (no external forces):

  $$\vec{p}_{\text{total initial}} = \vec{p}_{\text{total final}}$$

• Applies in all directions independently.

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COLLISIONS

Elastic Collisions

• Momentum and KE conserved.

• Example: gas molecule collisions.

Inelastic Collisions

• Momentum conserved, KE not conserved (some converted to heat/sound).

• Completely inelastic: Objects stick together after collision.

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CENTER OF MASS (COM)

• Point where total mass of system is considered concentrated.

• Position (discrete masses):

  $$x_{\text{cm}} = \frac{\sum m_i x_i}{\sum m_i}$$

• Moves as if all mass & external forces act there.

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ROCKET PROPULSION

• Based on momentum conservation.

• Equation of motion (no external force):

  $$m \frac{dv}{dt} = -v_{\text{ex}} \frac{dm}{dt}$$

  where $v_{\text{ex}}$ = exhaust velocity relative to rocket.

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