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Updated on 02nd March, 2023 , 3 min read
An impulse is the sum of a force, F, over the period of time it acts, t. Since force is a vector quantity, impulse also belongs to this category. When an object receives an impulse, it experiences an equivalent vector change in its linear momentum and also in the direction that results.
SI unit: newton-second (N⋅s) (kg⋅m/s in SI base units)
Other units: pound⋅s
The sum of a particle's mass and velocity is known as momentum. Momentum has a magnitude and a direction because it is a vector quantity. The second law of motion of Isaac Newton states that the force acting on a particle is equal to the time rate of change of momentum.
For example,
If a football game ends in a tie, each team is given a certain number of penalty shots. As a result, when the player kicks the ball, which is at rest and has no momentum, to shoot for the goal, the momentum increases due to the development of velocity. This sudden change in momentum causes an impulsive force to be generated. The impulsive force assists the ball in traveling long distances in a short amount of time.
The impulse is a large force that acts for a very short period of time. It is represented by J
The Impulse Formula is expressed as
J=F×t
Where,
Impulse can also be defined as the rate of change of momentum.
J=m×v
Where,
Velocity is expressed as
v=vf – vi
Where,
As a result, the Impulsive force is expressed as
f=mvf−vit
The impulsive force is articulated in Newton(N) and the impulsive force is articulated in Kgms-1.
The following equation can be used to calculate Impulse:
J = m * Δv
To put it simply,
Impulse = mass (m) * (Velocity2-Velocity1)
We can calculate the unit of impulse using the above equation:
Mass = in kg
Velocity = in m/s
J = kg . m/s or N.s
Q1.After a free fall from a height, a 5-gram ball lands on the ground. Gravitational acceleration, g = 10 ms-2. The ball has a velocity of 6 ms-1 before colliding, and it is reflected upright at 4 m/s after the collision. Determine the impulse.
Ans:
Mass of the ball (m) = 5 gm = 0.005 kg
Before collision, velocity of ball (vo) = -6 m/s
After collision, velocity of ball (vt) = 4 m/s
The plus and minus signs indicate that the direction before the collision is opposite the direction after the contact.
Since we need to find out Impulse (J), so the solution will be
Impulse (J) = Total change in momentum (Δp)
J = Δp = m * vt – m * vo
= m * (vt – vo)
J = (0.005)(4 – (-6)) = (0.005)(4 + 6) = (0.005)(10) = 0.05 N.s (Ans.)
Q2. A batter hits a straight ball at the bowler while maintaining its initial 12 m/s speed. If the ball's mass is 0.15kg, calculate the impulse transferred to it.
Ans: Given vi (Initial Velocity) = 12 m/s
vf (Final Velocity) = -12m/s
m (mass) = 0.15kg
Impulse is articulated as J = m * vf – m * vi
= m (vf – vi)
= 0.15 Kg (-12 -12) m/s = -3.6N.s
So, impulse = -3.6N.s (Ans.)
The product of the average net force acting on an object for a given duration is often defined as the impulse. The equation for impulse is given as; J = F⋅Δt. Impulse, like force, is a vector quantity with a directional component.
An impulse is a specific amount of force applied for a specific amount of time to cause a change in momentum.
Momentum is defined as the resistance of an object to stopping. The terms "impulse" and "momentum" are synonymous. The term "impulse" refers to a unit of measurement that expresses the effect of a net force applied to an object. The symbol of momentum is p.
Some common applications include hitting a ball, a car accident, Golf, karate and so on.
The unit of impulse is kg meter per second (kgm/s) or Newton second (Ns).
The impulse is usually represented by the variable J (not to be confused with the polar moment of inertia, which is also represented by J), and momentum is defined as a body’s mass multiplied by its velocity.