Impulse Calculator
What is Impulse?
In physics, Impulse ($J$) is the quantity that describes the effect of a force acting over a period of time. It is what causes objects to change their velocity.
Think about kicking a soccer ball. The "Impulse" is the force of your foot multiplied by the split second it is in contact with the ball. That brief interaction transfers energy to the ball, sending it flying.
The Two Formulas
Impulse connects two major concepts: Force and Momentum. This gives us two ways to calculate it.
1. The Force Definition
- F (Force): The average force applied (Newtons).
- Δt (Time): How long the force was applied (Seconds).
2. The Impulse-Momentum Theorem
This theorem states that the Impulse applied to an object is exactly equal to its Change in Momentum ($\Delta p$).
If you know how much an object weighed and how much its speed changed, you know the Impulse, even if you don't know the Force or Time.
The Science of Airbags (Saving Lives)
Why do cars have airbags? It all comes down to the Impulse formula: $F = J / \Delta t$.
In a car crash, your body has a specific amount of Momentum that must be reduced to zero. This means the Impulse ($J$) required to stop you is fixed.
- Dashboard (Hard Surface): Stops you instantly (e.g., 0.01 seconds). Since time ($\Delta t$) is tiny, the Force ($F$) must be HUGE. This causes injury.
- Airbag (Soft Surface): Slows you down gradually (e.g., 0.2 seconds). By increasing the time ($\Delta t$), the Force ($F$) is drastically reduced.
Follow Through in Sports
Coaches always tell golfers, baseball players, and tennis players to "follow through." Why?
To hit the ball farther, you want to maximize velocity ($v$). To maximize velocity, you need to maximize Impulse ($J$).
Since you can only swing so hard (Force is limited by your strength), the only way to get more Impulse is to increase the contact time ($\Delta t$). Following through ensures the bat/club stays in contact with the ball for the maximum possible time, transferring more energy.