Impulse and force calculator
Impulse is force times time, and it equals the change in momentum. Stretching the time reduces the force.
s
Average force
-7500N
- Impulse
- -1125 N s
- Deceleration in g
- 10.197
- Force if the contact lasted ten times longer
- -750
Show the working
- Mass = 75
- Initial speed = 15
- Final speed = 0
- Contact time = 0.15
- Impulse = 75 * (0 - 15) = -1125
- Average force = -1125 / 0.15 = -7500
- Deceleration in g = abs(-7500) / (75 * g0) = 10.1972
- Force if the contact lasted ten times longer = -1125 / (0.15 * 10) = -750
Values are shown to six significant figures here; the arithmetic itself runs on exact fractions and is only rounded where a number is printed.
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The formula
- impulse J = F t = m (v - u)
- F = m (v - u) / t
Airbags, helmets and landing mats all work by increasing t. The impulse is fixed; only the peak force is negotiable.