A 1,500-kg car is moving to the right at 14 m/s before it crashes into a wall and bounces back to the left at 6 m/s. The impact lasts for 0.5 seconds, what is the average force exerted during the impact

Why does the equilibrium position of the spring change when a mass is added to the spring? will the mass oscillate around the new equilibrium position of the spring or the previous position without a mass attached to the spring? if the equilibrium position of the spring changes by 20 cm (assuming no initial mass) when a mass is added to the spring with constant 4.9 kg/s^2, what is the mass of the object attached to the spring?