posted by Anonymous .
A 900 kg car rolling on a horizontal surface has speed v = 55 km/h when it strikes a horizontal coiled spring and is brought to rest in a distance of 2.2 m. What is the spring stiffness constant of the spring?
the KE of the car= PE of the spring
1/2 m v^2=1/2 k x^2
solve for k
velocity has to be in m/s