Glossary
Kinetic Energy
The energy an object possesses due to its motion, calculated as half its mass times the square of its speed. Unlike momentum, it is a scalar quantity.
Example:
A small, fast-moving bullet might have less momentum than a slow-moving bowling ball, but it possesses significantly more kinetic energy due to its high velocity squared.
Linear Momentum
A measure of mass in motion, combining an object's mass and velocity. It quantifies the tendency of a moving object to continue its motion.
Example:
A massive freight train moving at a high speed possesses enormous linear momentum, making it difficult to stop quickly.
Newton's Second Law (F = dp/dt)
The more general form of Newton's Second Law, stating that the net external force acting on an object or system is equal to the rate of change of its linear momentum with respect to time.
Example:
A rocket engine operates based on Newton's Second Law (F = dp/dt), where the thrust force is generated by the rapid expulsion of high-velocity exhaust gases, causing a significant change in the system's momentum.
Vector Quantity
A physical quantity that possesses both magnitude (size) and direction. For momentum, this means its direction is the same as the object's velocity.
Example:
When analyzing a collision, understanding the vector quantity of each object's momentum is crucial to predict the direction and speed of the objects after impact.