Ballistic Ping Pong Ball vs. Tennis Ball at 450km/h!

Many years ago (1997 or so) I lived about 100 feet from Interstate 10, east of Los Angeles. There was a brick sound wall between my house and the freeway, but there was still plenty of noise. One Saturday , I heard a long, low screeching sound followed by smash... smash... smash... smash... as a semi plowed into multiple stopped cars. Since we couldn't see, we had to make guesses, but 15 minutes later, we saw and heard an emergency helicopter landing on the freeway to rush folks to the hospital.

Semis in collisions are scary deadly.