After working on the handout’s 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

What’s the elevator’s acceleration? 1.-6 m/s 2.0 m/s/s m/s/s