Question

1. To find the height of an overhead power line, you throw a ball straight upward. The ball passes the line on the way up after 0.90 s, and passes it again on the way down 1.4 s after it was tossed.
(a) What is the height of the power line?
m
(b) What is the initial speed of the ball?
m/s

2.While riding on an elevator descending with a constant speed of 3.4 m/s, you accidentally drop a book from under your arm.
(a) How long does it take for the book to reach the elevator floor, 1.4 m below your arm?
s
(b) What is the book's speed relative to you when it hits the elevator floor?
m/s

Answer 1

1) look at this website: www.physicsforums.com/threads/determining-height-of-powerline-by-throwing-ball-upward.507882/

2)look at this website: h ttps://answers.yahoo.com/question/index?qid=20130731133731AAq5Nfi

Answer 2

and look at the similar question