(Solved): 8. A train rolls at a constant speed of \( 10 \mathrm{~m} / \mathrm{s} \) across a horizontal track ...

8. A train rolls at a constant speed of \( 10 \mathrm{~m} / \mathrm{s} \) across a horizontal track. A child standing on the flatbed of the train throws a ball so that it appears to move straight up to an observer standing next to the track. a. What is the horizontal speed of the ball relative to the observer? b. What is the horizontal speed of the ball relative to the train? c. If the ball is also thrown upward with a speed of \( 20 \mathrm{~m} / \mathrm{s} \), what is the overall initial speed of the ball relative to the train?