Usually impulse is the physical quantity that is the change in momentum due to a force or a torque.
Suppose a ball of 2 kg is moving with a velocity of 5 m/s. A force acts on it for 0.1 sec and the ball now moves at 10 m/s.
Linear Impulse (vector) is the change in linear momentum p due to this force during short time
J = Δp = p1 - p2 = d p / dt = Δ p /Δ t
magnitude of J = 2 * 10 - 2 * 5 = 10 kg-m/sec
It is equal to the force * time duration.
Similarly, change in angular momentum L due to a torque (during a short period Δt) acting on a rotating object of mass m and moment of inertia I, and initial angular velocity ω1 and final angular velocity ω2, is called angular impulse ΔL. It is also a vector.
L = I ω
ΔL = I (ω2 - ω1)
= angular torque * time duration = T * t = I * α * t =
its units are kg-meter² / radian / sec