1. Dr. Joseph W. Howard ©Spring 2008 Galileo Free Fall Acceleration Due to the Earth’s Gravity Free Fall Acceleration Due to the Earth’s Gravity When dropped, these two different masses will fall with the same acceleration ! (g ≈ 9.8 m/s 2 ) When dropped, these two different masses will fall with the same acceleration ! ( g ≈ 9.8 m/s 2 )

2. Dr. Joseph W. Howard ©Spring 2008 Conceptual Challenge Ask yourself these questions and answer them. Ask yourself these questions and answer them. 1.As a ball falls, does it speed up, slow down, or move with a constant speed? 2.What is the direction of the velocity and acceleration of a ball falling? 3.When tossed upward, does a ball speed up, slow down, or move with constant speed? 4.What is the direction of the velocity and acceleration of a ball tossed upwards? 5.Draw a vector picture of a ball tossed upwards at 29.4 m/s that is allowed to eventually fall. 1.As a ball falls, does it speed up, slow down, or move with a constant speed? 2.What is the direction of the velocity and acceleration of a ball falling? 3.When tossed upward, does a ball speed up, slow down, or move with constant speed? 4.What is the direction of the velocity and acceleration of a ball tossed upwards? 5.Draw a vector picture of a ball tossed upwards at 29.4 m/s that is allowed to eventually fall.

3. Dr. Joseph W. Howard ©Spring 2008 0s 1s 2s 3s, 0 m/s 6s 5s 4s 29.4m/s 19.6m/s 9.8m/s 29.4m/s 19.6m/s 9.8m/s = 9.8 m/s 2 downward = acceleration of gravity Notice that when the ball is traveling upward and downward that the acceleration of gravity is always downward “Slowing down” the ball’s velocity is upward, the acceleration is downward “Speeding up” the ball’s velocity is downward, the acceleration is downward What is the acceleration at the very top? What is the acceleration at the very top?