A 1650 kg car rolling on a horizontal surface has a speed of 20 km/hr when it strikes a horizontal coiled spring and is brought to rest in a distance of 3.5 m. What is the spring constant (in N/m) of the spring? (Ignore nonconservative forces such as friction.)
Wc = m*g = 1650kg * 9.8N/kg = 16,170 N.=
Wt. of car.
k = 16,170N./3.5m. = 4620 N/m.