1. Day 8 At A Glance We have one major goal for today:
1) Understand how to apply the ideas of kinematics to different situations.

2. NEXT WEEK
1) Makeup quiz: If you are taking it, sign the sheet with if its happening on MONDAY or TUESDAY.
Mega lab due date: 9/19 (A), 9/20 (B)

3. Day 8 At A Glance So today will have the following:
A crazy ton of examples that will allow you to discover what is required of you thinking wise from the last 1.5 weeks.
And reminders of HOW to think, strategies to use, and ways to become the physicist you want to be!

4. LABY McLABSON
Lets get it done
Format….examples

5. Strategies to use
Make a chart of the ‘5’ variables that a kinematics problem can have.
Include a + or – on each one except for time.
If you don’t know a variable, leave it blank.
Trying to find it? Put a ? in.
If there are multiple time periods or accelerations, make a table for EACH section
Once you know 3 of the 5, you can get the rest

6. The Big 5 Vo : The INITIAL velocity of a time segment
Vf or V: the FINAL velocity of a time segment
ΔX : the Displacement (also X – X0) during a time segment, where X and Xo are positions
a : The acceleration during a time segment
t : The amount of time during an acceleration

7. We must both do the math as well as understand what they mean in words
Lets hand out the formula sheet…

8. An object goes from +2m/s to +12m/s over 4 seconds, then from +12m/s to 22 m/s after another 5 seconds.
A student wants to determine the total distance the object went.

9. An object goes from +2m/s to +12m/s over 4 seconds, then from +12m/s to +22 m/s after another 5 seconds.
Can the student use the following scenarios to find the displacement: Vo is +2, Vf is +22m/s, t = 9 sec, Xo is 0, the goal is Xf?

10. An object goes from +2m/s to +12m/s over 4 seconds, then from +12m/s to 22 m/s after another 5 seconds.
A student wants to determine the total distance the object went.

11. Question What affects the speed of something in the air? Mass?
Surface Area?
Temp?
Air Pressure?

12. KEY IDEAS…THE BEGINING
Mass has no effect on the speed due to gravity
Always neglect air resistance unless it is completely clear from the problem that it is important. “TERMINAL VELOCITY”

13. An Example
You toss a ball in the air at 5m/s. It ends back in my hand. How long did it take?

14. You Try
You toss a ball in the air at 5m/s. It ends back in my hand. How high up did it go?

15. An Example…YOU TRY AT SEATS
The Majesty of the animal kingdom.
A cat is 18m off the ground. It jumps up at 1m/s. Around how long does it take to fall?
A) 5 seconds
B) 1 second
C) 2 seconds
D) 4 seconds

16. An Example QUADRATIC! OR USE LOGIC! Strategies….
Use your calculator
OR USE LOGIC!
1m/s is virtually like 0m/s overall.

18. KEY IDEAS WITH THESE
When it comes to multiple choice with math, the numbers are usually easy to work with.
Math tricks like figuring out what a comparable (and easier to imagine) situation to imagine is very profitable.

19. On The Boards
A ball is dropped from rest near Earth. Neglect air resistance. Justify your answers
1) About how far will the ball fall in 3 seconds?

20. On The Boards
A ball is dropped from rest near Earth. Neglect air resistance. Justify your answers
2) The same ball is dropped on the moon, where acceleration is 1/6 that of Earth. How far will the ball fall in 3 seconds?
A) 1/6 as far as it did on Earth
B) 1/36 as far as it did on Earth
C) The same distance as the ball on Earth
D) 6 times as far as the ball on Earth
E) 36 times as far as the ball on Earth

21. Key Ideas With Determining How A CHANGE AFFECTS A RESULT
Look at the equation. If the variable in question or the result variable are not direct (i.e. ½, squared, etc), then an increase/decrease is easy to determine.

22. And More
A panda throws two stones from the top of a building at 20m/s. One is thrown down, one is thrown up. Compare the accelerations of the two bricks
A) Both have same acceleration
B) Thrown up has more acceleration
C) Thrown down has more acceleration
D) not enough info to solve

23. And More
A panda throws two stones from the top of a building at 20m/s. One is thrown down, one is thrown up. The first one hits after time t1. How much later before the 2nd one hits?
A) 5s
B) 4s
C) 3s
D) not enough info to solve

25. LETS TRY ONE In which case will a car move the greatest distance?
A) A car with speed V1 travels at constant speed for time t1 and accelerates to V2 in time t2.
B) A car with speed V1 accelerates to speed V2 in t1 seconds and then travels at speed V2 for t2 seconds.
C) Can’t do it without knowing all 4 values.

27. LASTLY
You drop ball A from a building. 1 second later you drop ball B. As time progresses, the difference in their speeds
A) Increases
B) Remains Constant
C) Decreases
D) Cannot be determined

28. LASTLY
You drop ball A from a building. 1 second later you drop ball B. As time progresses, the distance between them
A) Increases
B) Remains Constant
C) Decreases
D) Cannot be determined