What should be the spring constant k of a spring designed to bring a 1260 kg car to rest from a speed of 88 km/h so that the occupants undergo a maximum acceleration of 5.0 g?
v2=v02 + 2a(x-x0
The Attempt at a Solution
First I converted 88km/h to 24.4 m/s
Then I found the F, by using F=ma
F= (1260) * (49) <--changed acceleration from g to m/s2
So I got 61740 for F
Then I decided to find x
I used the velocity equation
0 = (24.4)2 + 2 * -49x
Solving for x gave me 6.08
Then I plugged that into the F=-kx equation
and I got k = 10155
But this is wrong! I even tried putting in -10155
What am I doing wrong? I don't understand.