Linear Momentum and Its Conservation in Physics

Conservation of Momentum

Total momentum before equals total momentum after collision.

Momentum

A vector quantity defined as p = mv.

Vector Quantity

A quantity with both magnitude and direction.

Elastic Collision

Collision where kinetic energy is conserved.

Inelastic Collision

Collision where kinetic energy is not conserved.

External Forces

Forces acting on a system from outside.

Internal Forces

Forces exchanged within a system.

Closed System

A system with no external forces acting.

Stationary Object

An object with zero initial velocity.

Momentum Equation

p = mA uA + mB vB.

Kinetic Energy

Energy of motion, calculated as Ek = 1/2 mv².

Common Velocity

Velocity of two objects moving together post-collision.

Mass of Trolley A

0.80 kg, initial mass before collision.

Mass of Trolley B

1.60 kg, twice the mass of Trolley A.

Initial Velocity of Trolley A

3.0 m/s, velocity before collision.

Momentum Before Collision

Calculated as 2.4 kg m/s for Trolley A.

Momentum After Collision

Expressed as 2.4 * vA+B for both trolleys.

Kinetic Energy Before Collision

3.6 J, total kinetic energy before impact.

Kinetic Energy After Collision

1.2 J, total kinetic energy after impact.

Collision Type Determination

Compare kinetic energy before and after collision.

Resultant External Force

Force causing momentum change in a system.

Opposing Vectors

Vectors that can cancel each other out.

Final Object in Inelastic Collision

Treated as single object with combined mass.

Momentum Conservation

Total momentum remains constant in collisions.

Change in Momentum

Difference in momentum before and after collision.

Kinetic Energy Equation

Ek = 1/2 mv² for kinetic energy.

Perfectly Elastic Collision

All kinetic energy retained post-collision.

Perfectly Inelastic Collision

Objects stick together after collision.

Velocity Components

Momentum split into x and y components.

Projectile Motion

Motion of an object thrown into the air.

Initial Velocity

Velocity of an object before impact.

Final Velocity

Velocity of an object after impact.

Mass of Ball

60 × 10⁻³ kg for the ball.

Relative Speed of Approach

Speed before collision in elastic collisions.

Relative Speed of Separation

Speed after collision in elastic collisions.

Kinetic Energy Transfer

Kinetic energy converted to other energy forms.

Crumple and Deform

Objects change shape during inelastic collisions.

Total Kinetic Energy

Sum of kinetic energies of colliding objects.

Examiner Tip

Momentum conserved, kinetic energy not always.

Velocity Calculation

Use cosine for horizontal component.

Negative Momentum Change

Indicates direction reversal after collision.

Head-on Collision

Direct impact between two objects.

Energy Conservation Comparison

Before and after kinetic energy equality check.

Vector Resolution

Breaking down vectors into components.

Collision Analysis Steps

Sequential approach to analyze collisions.