1. The problem statement, all variables and given/known data The Hungarian national highway M7 is made of concrete blocks 4m long. The joints have a small gap. Józsi have a mass of 80 kg. He owns a Polski Fiat, which is lowered by 10 cm when he sits in. At what speed would Józsi's car disintegrate? 2. Relevant equations v = l/t F = -k*dx F = m*a g = 9.81 kg*m/s 3. The attempt at a solution I remember I have solved it once (maybe with other numbers), but the road got some asphalt coating since.