It can look dumb, but I always had this question as a kid, what physical principles would prevent this?

    • underwire212@lemm.ee
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      2 hours ago

      That’s the thing. The math says they’re both correct, and that it depends on the viewpoint of the observer.

      I’m inside a car moving at 60 mph. I throw the ball forward (let’s ignore air resistance) at 30 mph.

      Me, who’s inside the car, sees the ball move forward at 30 mph.

      You, who’s outside the car, sees the ball move at the car’s speed PLUS the throw speed (60 + 30 =90 mph)

      So, the ball is moving both at 30 mph and 90 mph. How can that be? It depends entirely upon your reference frame (inside the car? Outside the car? Inside another car moving at 40 mph?). The ball moves at all these speeds, and they are all “correct” within universal terms.