HW Due Place both in In Box (POGIL page 2…… and the worksheet) HW Worksheet – given out at end of class Quest Jan 23 (B day) ***There is a REALLY GOOD review PowerPoint on my website…*** Do Now 1.Take one and complete BOTH SIDES. May work with peers.
Transcript
Slide 1
Slide 2
HW Due Place both in In Box (POGIL page 2 and the worksheet) HW
Worksheet given out at end of class Quest Jan 23 (B day) ***There
is a REALLY GOOD review PowerPoint on my website*** Do Now 1.Take
one and complete BOTH SIDES. May work with peers.
Slide 3
A bug and the windshield of a fast moving car collide. Tell
whether the following statements are true or false, and EXPLAIN
your reasoning: a. The forces of impact on the bug and on the car
are the same size. 1.True 2.False 3.Not enough info 4.Not quite
sure TRUE! FORCES COME IN PAIRS!
Slide 4
A bug and the windshield of a fast moving car collide. Tell
whether the following statements are true or false, and EXPLAIN
your reasoning: b. The impulses on the bug and on the car are the
same size. 1.True 2.False 3.Not enough info 4.Not quite sure TRUE!
SAME FORCE, SAME CONTACT TIME
Slide 5
A bug and the windshield of a fast moving car collide. Tell
whether the following statements are true or false, and EXPLAIN
your reasoning: c. The changes in speed of the bug and on the car
are the same size. 1.True 2.False 3.Not enough info 4.Not quite
sure FALSE! COMMON SENSEDO YOU NOTICE THE CAR SLOW DOWN? DOES THE
BUG NOTICE A CHANGE?
Slide 6
A bug and the windshield of a fast moving car collide. Tell
whether the following statements are true or false, and EXPLAIN
your reasoning: d. The changes in momentum of the bug and on the
car are the same size. 1.True 2.False 3.Not enough info 4.Not quite
sure TRUE! m v = m v Not to mention, Impulse = change in momentum,
and we already determined they have the same impulse
Slide 7
BugWindshield Ft m vm v m vm v Same Impulse Same change in
momentum Diff. masses and velocity changes!
Slide 8
Does a larger force always produce a larger impulse on an
object than a smaller force? Explain. 1.Yes 2.No 3.Not enough info
4.Not quite sure No not always!! F t = F t (1 N) (100s) = (10
N)(5s) 100 Ns = 50 Ns
Slide 9
YES/NO:____ EXPLANATION: A fully dressed student with a
backpack is at rest in the middle of a pond on perfectly
frictionless ice and must go to shore. Can this be accomplished?
Use KEY TERMS to explain: 1.Yes 2.No 3.Not enough info 4.Not quite
sure Yes throw the backpack! Force = Force, Impulse = Impulse
Slide 10
HW that was due today (workseet) Worksheet Texts open if needed
3 minutes to review with peers in the FRONT of the classroom
Gossiping/ being off task will result in you going back to your
seat and will guarantee the teacher will call on you. Then, we are
rapidly popcorning!
Slide 11
QUESTIONS ABOUT 24 or 26?
Slide 12
A bicycle has a momentum of 24 kgm/s. What momentum would the
bicycle have if it had a. twice the mass and was moving at the same
speed? TWICE as much! m v = p 4. 6 = 24 So. 8. 6 = 48
Slide 13
A bicycle has a momentum of 24 kgm/s. What momentum would the
bicycle have if it had b. the same mass and was moving with twice
the speed? TWICE as much! m v = p 4. 6 = 24 So. 4. 12= 48
Slide 14
A bicycle has a momentum of 24 kgm/s. What momentum would the
bicycle have if it had c. one-half the mass and was moving with
twice the speed? Same! m v = p 4. 6 = 24 So. 2. 12 = 24
Slide 15
A bicycle has a momentum of 24 kgm/s. What momentum would the
bicycle have if it had d. the same mass and was moving with
one-half the speed? HALF as much! m v = p 4. 6 = 24 So. 4. 3=
12
Slide 16
A bicycle has a momentum of 24 kgm/s. What momentum would the
bicycle have if it had e. three times the mass and was moving with
one-half the speed? 1.5 times as much! m v = p 4. 6 = 24 So. 12. 3
= 36
Slide 17
A bicycle has a momentum of 24 kgm/s. What momentum would the
bicycle have if it had f. three times the mass and was moving with
twice the speed? 6 times as much! m v = p 4. 6 = 24 So. 12. 12 =
144
Slide 18
Recap Last class, we talked about impulse changing momentum.
This class (and the next 2 classes), we are going to talk about
what happens if that impulse occurs during 2 scenarios: When
bouncing occurs When a collision occurs
Slide 19
POGIL from last class 10 minutes Take out your notes from last
class and go to the demo section. (Nerf Guns, Ping Pong Balls,
Toppling) You will be shown the Nerf Gun and Toppling Demos, and
you will get to try the Ping Pong Demos. BEFORE THAT. I want you to
consider the following question (write & answer in your notes)
Would a head-on collision between two cars be more damaging to the
occupants if the cars stuck together or if the cars rebounded
(bounced) upon collision? (Assume the time of the collision is the
same.)
Slide 20
Would a head-on collision between two cars be more damaging to
the occupants if the cars stuck together or if the cars rebounded
(bounced) upon collision? (Assume the time of the collision is the
same.) 1.When the cars stick 2.When the cars bounce 3.Doesnt matter
either way 4.Not sure!
Slide 21
POGIL from last class Cross out pages 3 4 look like this:
unless you want to challenge yourself to try what the Geo kids are
doingthen, feel free to try them at home and check!
Slide 22
POGIL from last class 10 minutes 1.You will be shown the Nerf
Gun and Toppling Demos, and you will get to try the Ping Pong
Demos. 2.Then, working in the FRONT of the classroom, you MUST
answer all questions A through F 3.Please review your HW on the
POGIL (page 2) Ensure that EVERYONE understands not only WHAT the
solutions are, but WHY they are what they areyou should be able to
transfer your thought process to other questions regarding similar
concepts. ***NOT SURE/ QUESTIONS? ASK A TEACHER!!!*** 1.Finish part
G Conclusion. 10 minutes to complete!
Slide 23
When is impulse larger? (heads down hands up) 1.When objects
bounce 2.When objects dont bounce 3.Doesnt matter either way 4.Not
sure!
Slide 24
Bouncing Impulses are greater when bouncing takes place Ft =
(mv) Falling flower pot hits your head Momentum stops Falling
flower pot hits your head and bounces off Momentum is reversed.
**Impulse to stop < impulse to throw it back again** 2(mv)
Karate chop Pelton wheel
Slide 25
Bouncing Important point: It only takes an impulse of mv to
stop the ball. It takes twice the impulse (2mv) to make it bounce)
Think about a bouncing ball: Before it hits the ground: Speed = v
Momentum = mv At the moment it hits the ground: Speed = 0 Momentum
= 0 After it leaves the ground: Speed = v Momentum = mv Impulse
needed to stop the ball = mv Total Impulse = 2mv Impulse needed to
accelerate the ball upwoard = mv Just like the medicine ball
exercise!!!
Slide 26
If the time of impact is long, the force will be milder. If the
time is very short, the force is powerful. When things bounce off
an object after hitting them, it is even more deadly in force
magnitude.
Slide 27
Slide 28
A rebound is a special type of collision involving:
Slide 29
a direction change which results in a velocity change.
Slide 30
A rebound is a special type of collision involving: a direction
change which results in a velocity change. Observe that the greater
the rebound effect, the greater the
Slide 31
A rebound is a special type of collision involving: a direction
change which results in a velocity change. Observe that the greater
the rebound effect, the greater the acceleration, momentum change,
and impulse.
Slide 32
A rebound is a special type of collision involving: a direction
change which results in a velocity change. Observe that the greater
the rebound effect, the greater the acceleration, momentum change,
and impulse. The result of the direction change is a large velocity
change.
Slide 33
HW that was due last class #11-13, p. 100 Texts open if needed
3 minutes to review with peers in the FRONT of the classroom
Gossiping/ being off task will result in you going back to your
seat and will guarantee the teacher will call on you. Then, we are
rapidly popcorning!
Slide 34
HW that was due last class #11-13, p. 100 Texts open if needed
we are rapidly popcorning! 11a) Visualize yourself on a skateboard.
When you throw a ball, do you experience an impulse? Yes push the
ball, and ball pushes you (force) for an amount of timeforce x time
= impulse!
Slide 35
HW that was due last class 11b) Visualize yourself on a
skateboard. When you catch a ball, do you experience an impulse?
Yes push the ball, and ball pushes you (force) for an amount of
timeforce x time = impulse!
Slide 36
HW that was due last class 11c) Visualize yourself on a
skateboard. When you catch a ball, and then throw it back, do you
experience an impulse? Yes push the ball, and ball pushes you
(force) for an amount of timeforce x time = impulse!
Slide 37
HW that was due last class 11d) Visualize yourself on a
skateboard. In which of the scenarios do you experience the largest
impulse? 1.Catch 2.Throw 3.Catch an throw 4.Same in all Catch and
throw its like bouncing! More velocity change, so more momentum
change, so more impulse!
Slide 38
HW that was due last class 12) Why is more impulse delivered
when bouncing occurs? More velocity change, so more momentum
change, so more impulse!
Slide 39
Go to your test seats Normal quiz procedures apply Open notes,
not open books No calc needed cell phones OUT and SILENT When done,
quiz in basket upside down and you may continue working on your HW
(make your hypotheses and try them) Open notes quest on Ch. 7 on
Jan. 23
Slide 40
HW that was due last class 13) Why is the Pelton wheel an
improvement over a wheel with flat blades?
Slide 41
Go to your test seats Normal quiz procedures apply Open notes,
not open books No calc needed cell phones OUT and SILENT When done,
quiz in basket upside down and take a copy of your: 1. Momentum
Conceptual review (HW) Start working on this it is HW!!! 2.And
Midterm Information Read the Midterm Information sheet tonight we
will answer any questions about it next class