Momentum, Impulse, and Energy

These flashcards cover the key concepts of momentum, impulse, and energy as discussed in the lecture, highlighting definitions, relationships, and fundamental laws.

Momentum

The product of the mass of an object and its velocity; a measure of the motion of an object.

Impulse

The quantity force multiplied by the time interval during which the force acts, which equals the change in momentum.

The law of conservation of momentum

In the absence of external forces, the total momentum of a closed system remains constant.

Elastic collision

A collision in which colliding objects rebound without lasting deformation or generation of heat; momentum is conserved.

Inelastic collision

A collision in which colliding objects become distorted and/or generate heat and possibly stick together; momentum is conserved.

Kinetic energy

The energy of an object due to its motion, calculated as one half of the mass multiplied by the velocity squared (KE =  mv²).

Potential energy

The energy stored in an object due to its position or configuration; gravitational potential energy is calculated as weight times height (PE = mgh).

Work

The product of force applied and distance moved in the direction of the force, measured in joules (W = Fd).

Power

The rate at which work is done, defined as work divided by time (Power = W/t), measured in watts.

Efficiency of a machine

The ratio of useful work output to total work input, expressed as a percentage.

Impulse-Momentum relationship

Impulse is equal to the change in momentum of an object that impulse acts upon (Impulse = (mv)).

System (Physics)

A defined collection of objects or particles under consideration, used to analyze interactions and energy transfers.

Work-Energy Theorem

The net work done on an object equals the change in its kinetic energy (W_{net} = \Delta KE).

Units of Momentum

Kilogram-meters per second (kg \cdot m/s).

Units of Impulse

Newton-seconds (N \cdot s) or Kilogram-meters per second (kg \cdot m/s).

Law of Conservation of Mechanical Energy

In an isolated system where only conservative forces do work, the total mechanical energy (sum of kinetic and potential energy) remains constant (KE + PE = constant).

Mechanical Energy

The sum of kinetic energy and potential energy within a system (ME = KE + PE).

Conservative Force

A force for which the work done in moving an object between two points is independent of the path taken (e.g., gravity, spring force).

Non-conservative Force

A force for which the work done depends on the path taken, often resulting in mechanical energy loss (e.g., friction, air resistance).

Units of Work and Energy

Joule (J), equivalent to Newton-meter (N \cdot m).

Perfectly Inelastic Collision

An inelastic collision where colliding objects stick together after impact and move as a single combined mass, conserving momentum but losing maximum kinetic energy.