We have online homework that checks our answers when input. I'm pretty confident about this problem, but it won't take my answers. 1. The problem statement, all variables and given/known data A student proposes a design for an automobile crash barrier in which a 1350-kg sport utility vehicle moving at 25.0m/s crashes into a spring of negligible mass that slows it to a stop. So that the passengers are not injured, the acceleration of the vehicle as it slows can be no greater than 5.00g. a) Find the required spring constant k. In your calculation, disregard any deformation or crumpling of the vehicle and the friction between the vehicle and the ground. b) Find the distance the spring will compress in slowing the vehicle to a stop. 2. Relevant equations W = (1/2)kx^2 (work done by spring) v^2 = vo^2 + 2a(x) (to find x given a) 3. The attempt at a solution I used 5.00(g) = 5(9.8) = 49 to find the maximum acceleration. I plugged this into v^2 = vi^2 + 2a(x) and got x = 6.38 m. This should be the answer to b), but the online homework program says it is wrong. I see no way to solve a) without b). I used W=(1/2)kx^2 (work done by a spring), set equal to (1/2)mv^2 (the kinetic energy of the car). Solving for k and plugging in values, I got 20731 N/m. The online homework program also rejected this answer.