Momentum & Impulse Flashcards

Momentum

• Defined as the quantity of motion an object possesses, related to both its mass and velocity.
• Momentum is calculated using the formula: momentum = mass × velocity.
• Greater mass and greater velocity result in greater momentum.

Impulse

• Impulse is the product of average force and the duration of time the force acts, represented as F × t.
• The impulse-momentum theorem states that the impulse on an object equals its change in momentum.

Key Relationships

• Objects at rest have zero momentum.
• Newton's second law indicates that the change in velocity is influenced by the applied force, formulated as a = F/m.
• Large changes in momentum require large impulses, which can result from either a large force acting over a short time or a small force over a longer duration.

Conservation of Momentum

• In a closed, isolated system, the total momentum remains constant before and after an interaction, described by the law of conservation of momentum.
• Equations for conservation of momentum can be expressed as:
  • P total initial = P total final
  • mv total initial = mv total final

Collision Scenarios

• For two objects colliding and sticking together, the equation is: m1v1 + m2v2 = (m1 + m2)v final.
• For elastic collisions where objects bounce off each other, the equation is: m1v1 initial + m2v2 initial = m1v1 final + m2v2 final.

Impulse in Collisions

• The force experienced by an object during a collision, acting for a specific duration, is termed impulse.
• Impulse specifically changes the momentum of an object.

Characteristics of Momentum

• Momentum is a vector quantity, possessing both magnitude and direction.
• Change in momentum can be calculated using the equation: p final - p initial.

Newton's Third Law and Collisions

• In collisions, both involved objects exert equal and opposite forces on each other, in accordance with Newton's third law.
• When analyzing forces during a collision, both objects experience the same force, impulse, and change in momentum.
• The object with the least mass experiences the greatest acceleration.

Misconceptions

• In an isolated system, the total momentum conserved means individual objects do not conservatively retain their own momentum; rather, the sum must remain constant.