impulse

physics

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Last updated

July 23, 2026

Quick Summary

Impulse in physics is defined as the product of force and the time interval over which it acts. It is equal to the change in momentum of an object. Momentum itself is the product of an object's mass and its velocity.1

Newton's second law of motion states that the rate of change of momentum is equal to the applied force. This relationship means that impulse can be used to calculate how much an object's momentum changes. Conversely, momentum can be seen as a measure of the time needed for a constant force to bring an object to rest.1

In the context of gas pressure, impulse is also relevant. A molecule experiences a change in momentum when it collides with a container wall. The impulse imparted to the wall by the molecule is equal and opposite to the impulse imparted to the molecule by the wall, according to Newton's third law. The sum of these impulses from all molecules hitting the wall results in the pressure exerted by the gas.2

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mechanics
Collisions
…integral is known as the impulse imparted to the particle. In order to perform the integral, it is necessary to know r at all times so that F may be known at all times. More realistically, Δ p is the sum of a series of small steps, such thatwhere F…
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…integral is known as the impulse imparted to the particle. In order to perform the integral, it is necessary to know r at all times so that F may be known at all times. More realistically, Δ p is the sum of a series of small steps, such thatwhere F…
Read More

gas
Pressure
…wall; during the collision an impulse is imparted by the wall to the molecule that is equal and opposite to the impulse imparted by the molecule to the wall. This is required by Newton’s third law. The sum of the impulses imparted by all the molecules to the wall is,…
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…wall; during the collision an impulse is imparted by the wall to the molecule that is equal and opposite to the impulse imparted by the molecule to the wall. This is required by Newton’s third law. The sum of the impulses imparted by all the molecules to the wall is,…
Read More

collision
…this nature are known as impulsive forces and, being difficult to measure or estimate, their effects are measured by the change in the momentum (mass times velocity) of the body. The ballistic pendulum is a device based on this principle.
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…this nature are known as impulsive forces and, being difficult to measure or estimate, their effects are measured by the change in the momentum (mass times velocity) of the body. The ballistic pendulum is a device based on this principle.
Read More