A ball is released from a tower at a height of 100 meters toward the roof of another tower that is 25 meters high. The horizonta
l distance between the two towers is 20 meters. With what horizontal velocity should the ball be imparted so that it lands on the rooftop of the second building?
-- During the time the ball is flying from the high roof to the low roof, it's going to fall (100-25) = 75 meters. How long does it take an object dropped from rest to fall 75 meters ?
Distance = (1/2) · (gravity) · (time)²
75 m = (4.9 m/s²) · (time)²
Time² = (75 m) / (4.9 m/s²) Time² = 15.31 sec² Time = √(15.31 sec²) = 3.91 seconds
So the ball has to cover the horizontal distance of 20 meters in 3.91 seconds.
