Physics for Scientists and Engineers: A Strategic Approach with Modern Physics (4th Edition)

Published by Pearson
ISBN 10: 0133942651
ISBN 13: 978-0-13394-265-1

Chapter 2 - Kinematics in One Dimension - Conceptual Questions - Page 58: 11


Toss a ball up in the air

Work Step by Step

Toss a ball straight up in the air. With an initial velocity (actually, it doesn't have to be straight up, it can be tossed at an angle, but that complicates this story a little) Take up to be (+y). (a) On its way up, the ball has the initial velocity gradually decreasing (but still positive) until it reaches its highest point. It is accelerating (decrease is change), and the acceleration vector points down, so the acceleration is negative. (b) Once it reaches the highest point, where its instantaneous velocity is zero, from there onward, it begins increasing its velocity, towards the ground, therefore negative. Free fall acceleration still points down as before, so it is negative also.
Update this answer!

You can help us out by revising, improving and updating this answer.

Update this answer

After you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.