Mr. Rossi's car, stopped at the traffic lights, is hit by that of Mr. Bianchi. Then later in court, claims that he was traveling at 50 km / h, but Mr. Rossi tthinks that mr. Bianchi was going much faster. After the collision the two cars got stuck and from the tracks on the asphalt it was possible to establish that, immediately after the collision, they were traveling at 30 km / h. Mr. Bianchi drove a car with a mass of 800 kg and Rossi a car with a mass of 1400 kg.
Does Bianchi tell the truth?

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