when an impulse is given to a particle, momentum is transferred from an external agent to that particle. What do they mean by external agent
what is really an impulse beside saying that its a change in momentum
external: outside the particle.
If your briefcase is lifted, and external force is the lifting agent.
An external agent refers to something or someone outside of the particle itself that is responsible for providing the impulse. In simpler terms, it is the object or force that causes the change in momentum of the particle.
An impulse can be defined as the product of force and time interval over which the force acts. In other words, it is the integral or total change in momentum experienced by a particle when a force is applied over a certain period of time. So, the concept of impulse goes beyond just saying that it is a change in momentum; it quantifies the magnitude and duration of the force acting on the particle.
Mathematically, impulse can be expressed as the product of force (F) and the time interval (Δt) over which the force acts:
Impulse = F * Δt
The SI unit of impulse is the Newton-second (Ns) or kilogram-meter per second (kg·m/s).
When we say "external agent" in the context of impulse and momentum, we are referring to any physical entity or force that causes the change in momentum of the particle. It could be a person, a machine, or any other object that exerts a force on the particle.
Now, let's understand what an impulse really is. Impulse is defined as the product of the force applied to an object and the time interval over which the force is applied. It can be mathematically expressed as:
Impulse (J) = Force (F) x Time (Δt)
Impulse represents a change in momentum. Momentum is a property of an object that depends on its mass and velocity. It is given by the equation:
Momentum (p) = Mass (m) x Velocity (v)
Since impulse is the change in momentum, we can also express it as:
Impulse (J) = Change in Momentum (Δp)
Therefore, by applying an impulse to a particle, we are basically applying a force over a specific period of time, which results in a change in momentum of that particle.