- #1
Dingoz
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Ive been trying to get my head around an equation for seatbelts. Hyperphysics has an auto calculator and I've been trying to do it algebraically and still cannot get the same answer.
Here is what i have done...
In relation to a car traveling at 50kmph with a driver which weighs 75kg and stops with in 1 foot.
Car Crash Example
m = 75 kg, initially traveling at 50kmph = 13.88888889m/s d= 30 cm
Distance time interval =
dt = 0.3 m / 13.88888889 m/s = 0.022 s
During this 220th’s of a second it is decelerated from 13.88888889 m/s to zero, so
a = dv/dt = 13.88888889 m/s / 0.022 s = 631 m/s^2
So the impact force is
F = m x a = 75 kg x 631 m/s^2 = 47348N ...
But it is completely different answer, i believe my acelleration calculation is wrong BUT cannot seem to find out how
Ive been trying to get my head around an equation for seatbelts. Hyperphysics has an auto calculator and I've been trying to do it algebraically and still cannot get the same answer.
Here is what i have done...
In relation to a car traveling at 50kmph with a driver which weighs 75kg and stops with in 1 foot.
Car Crash Example
m = 75 kg, initially traveling at 50kmph = 13.88888889m/s d= 30 cm
Distance time interval =
dt = 0.3 m / 13.88888889 m/s = 0.022 s
During this 220th’s of a second it is decelerated from 13.88888889 m/s to zero, so
a = dv/dt = 13.88888889 m/s / 0.022 s = 631 m/s^2
So the impact force is
F = m x a = 75 kg x 631 m/s^2 = 47348N ...
But it is completely different answer, i believe my acelleration calculation is wrong BUT cannot seem to find out how