After working on the handouts first column Gravity = constant downwards acceleration. Rate = 9.8 m/s per second (9.8 m/s/s) [Trivia: 32 ft/s/s] One more clicker question related to harder problem. Quick Quizzes 2.6, 2.7 with clickers (coming in a few slides). Quick Quiz 2.8 is a good question to help you understand acceleration. An object is tossed upwards into the air. On the way up, what is the velocity? 1.Upwards (+) 2.Downwards (-) 3.Zero An object is tossed upwards into the air. On the way down, what is the velocity? 1.Upwards (+) 2.Downwards (-) 3.Zero An object is tossed upwards into the air. At the top, what is the velocity? 1.Upwards (+) 2.Downwards (-) 3.Zero An object is tossed upwards into the air. After leaving your hand but while flying upwards, which way is the acceleration? 1.Upwards (+) 2.Downwards (-) 3.Zero An object is tossed upwards into the air. On the way down, which way is the acceleration? 1.Upwards (+) 2.Downwards (-) 3.Zero An object is tossed upwards into the air. At the top, what is the acceleration? 1.Upwards (+) 2.Downwards (-) 3.Zero A tennis player on serve tosses a ball straight up. While the ball is in free fall, does its acceleration: 1.Increase the whole time 2.Decrease the whole time 3.Increase then decrease 4.Decrease then increase 5.Remain constant As the tennis ball travels through the air, its speed: 1.Increases the whole time 2.Decreases the whole time 3.Decrease then increase 4.Increase then decrease 5.Remain constant Do first falling from tall building question on handout Discuss next problem where ball is tossed upwards. Before solving anything ask the next clicker question Will the speed when it hits the ground be than m/s (when dropped) 1.Faster 2.Slower 3.Same speed What about being tossed downwards? What changes in the formulas we did on the board? Next clicker question. Two objects are tossed. One is tossed upwards +10 m/s. One is tossed downwards -10 m/s. Which is moving fastest when it hits the ground? 1.Upwards tossed object 2.Downwards tossed object 3.Both moving same speed 4.Not enough information given Ball landing on moving elevator Describe situation Ask class for written sentence or two, in groups. Pick 3 groups to read answers aloud Before going over the answer, try next two clicker questions The instant before the ball lands on the elevator, which is moving faster? 1.Ball 2.Elevator 3.Same Which is the same for the ball & elevator when the ball lands on elevator? 1.Position 2.Velocity 3.Acceleration Whats the elevators acceleration? 1.-6 m/s 2.0 m/s/s m/s/s