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Overview
Impulse describes how a force acting over a time interval changes an object's momentum. It is especially important in collisions, catches, hits, rebounds, recoil, and safety systems.
Force and Time
Impulse depends on both force and time. A large force for a short time and a smaller force for a longer time can produce the same impulse.
Impulse-Momentum Theorem
The impulse-momentum theorem states that impulse equals change in momentum. It links force over time to changes in motion.
Force-Time Graphs
On a force-time graph, the area under the curve represents impulse. This works even when force varies during the interaction.
Collision Safety
Airbags, crumple zones, helmets, mats, and padding reduce peak force by increasing the time over which momentum changes.
Sports Examples
Athletes use impulse when catching, throwing, kicking, landing, and following through during strikes.
Direction of Impulse
Impulse is a vector quantity. It points in the direction of the average net force and the change in momentum.
Common Mistakes
A common mistake is treating impulse as the same as force. Impulse includes time as well as force.
Applications
Impulse appears in vehicle safety, sports, rockets, manufacturing impacts, protective gear, and biomechanics.
Why This Matters in Physics
Impulse connects Newton's laws to momentum and real collision behavior.