Mechanics
Impulse
Impulse equals change in momentum.
Variables
JN·s
Impulse
Change in momentum
In SI units: kg·m/s
FN
Average force
Force during collision
In SI units: kg·m/s²
Δts
Time interval
Duration of force
Allowed values: greater than 0
Δpkg·m/s
Change in momentum
Final - initial momentum
Derivation
From F = dp/dt, integrate: J = ∫F dt = Δp.
Your notes
0/5000
Check value
Round inputs run through this page's calculator. Use it to test your own working or a rearranged form. It is a test case, not a real-world example.
- F = 2 N (Average force)
- Δt = 3 s (Time interval)
Result: J = 6 N·s
Other mechanics formulas with the same quantities
- Velocity (Kinematics) shares Time interval
- Acceleration (Kinematics) shares Time interval
- Angular Velocity (Rotational Motion) shares Time interval
- Angular Acceleration (Rotational Motion) shares Time interval
Where this formula is listed
- Mechanics formulas, under Momentum, alongside Elastic Collision (1D), Perfectly Inelastic Collision and Coefficient of Restitution.
- In the mechanics list it comes after Momentum and before Elastic Collision (1D).
- Mechanics formula sheet, one of 58 formulas printed with symbol keys and SI units.
- The full formula index, grouped by category and topic.
Common questions
What is the Impulse formula?
Impulse is written J = FΔt = Δp. Impulse equals change in momentum. It belongs to Mechanics, under Momentum.
What are the units in J = FΔt = Δp?
In SI units, J is impulse, measured in kg·m/s; F is average force, measured in kg·m/s²; Δt is time interval, measured in s; Δp is change in momentum, measured in kg·m/s.
How is the Impulse formula derived?
From F = dp/dt, integrate: J = ∫F dt = Δp. The result is J = FΔt = Δp.