Momentum and Our Dynamics Test

Okay this is Benofschool and this is the scribe for today.

We got our last test back and I am disappointed in my mark =(
Anyways here are the answers:

1.
2.
3. F_g = 103 N

4. F_|| = 11226 N

5. a= 1718.75 m/s² then use it to find F_resistance = -51.6 N

6a) F_n = 4410 N

b) F_a = 1500N

7a) F_|| = 94.5 N

b) F_n = 112.6 N then use it to find F_f = 24.7 N

c) F_net = 69.7 N

d) a = 4.65 m/s²


After correcting the test that I did horribly on we corrected chapter 9.1 study guide on Impulse and Change in Momentum

The blanks are filled in this order:

Momentum and Impulse
1) velocity 2) mass 3) mass 4) velocity 5) vector 6) the same as 7) p=mv 8) momentum

9) mass 10) velocity 11) kilogram x metre/ second 12) force 13) time interval 14) the same as

15) newton x second 16) momentum 17) impulse-momentum 16) second (2nd)

We were not required to do Angular Momentum

So then we received a 2 page booklet on Impulse and Momentum and I think should be done for tomorrow for homework.

This is the scribe for today and the next scribe will be Tony

First Week of Autumn

A dinosaur from the future came in to our class one day and ate the previous scribe. Then it ran away. Since the previous scribe is unable to scribe and I'm due for scribing anyways (yes, scribing is worth marks), I'm taking advantage of this blog drought as I do this post over the weekend. Here's an abbreviated overview of what we did Friday, September 26 to Monday, September 22nd.

FRIDAY, SEPTEMBER 26

• Redo Coefficient of Sliding Friction Lab
• Chapter 9 Study Guide (Impulse and Change in Momentum and The Conservation of Momentum) Worksheet (homework)
  
• Chapter 7 Momentum Worksheet (homework)
  

THURSDAY, SEPTEMBER 25

• Sang along to the M Times V song
• Watched Momentum Video (same-same guy) (5 points and hand-in)
  

WEDNESDAY, SEPTEMBER 24

• Dynamics Test

TUESDAY, SEPTEMBER 23

• Corrected Forces Review and Forces Evaluation: Using Concepts

MONDAY, SEPTEMBER 22

• Forces Review, Forces Enrichment, Forces Evaluation: Using Concepts, Frictional Forces, and Advanced Forces was assigned last Friday. These should be done by now.
• 5.2 Using Newton's Law: Read pp. 93-103. Questions #16, 18, 19, 22, 23 (pp. 123-126).
• 6.3 Application of Vectors: Read pp. 123-126. Questions #31, 35 (p. 131)

5.2 Using Newton’s Law Read pp. 98-103 Questions #16, 18, 19, 22, 23 (pp. 106-107)

16. You are driving a 2500.0-kg at a constant speed of 14.0 m/s along an icy, but straight and level road. While approaching a traffic light, it turns red. You slam on the brakes. Your wheels lock, the tires begin skidding, and the car slides to a halt in a distance of 25.0 m. What is the coefficient of sliding friction (μ) between your tires and the icy roadbed?

18. A 4500-kg helicopter accelerates upward at 2 m/s2. What lift force is exerted by the air on the propellers?

19. The maximum force a grocery bag can withstand and not rip is 250 N. If 20 kg of groceries are lifted from the floor to the table with an acceleration of 5 m/s2, will the bag hold?

22. A sled of mass 50 kg is pulled along snow-covered, flat ground. The static friction coefficient is 0.30, and the sliding friction coefficient is 0.10.
a. What does the sled weigh?
b. What force will be needed to start the sled moving?
c. What force is needed to keep the sled moving at a constant velocity?
d. Once moving, what total force must be applied to the sled to accelerate it 3.0 m/s2?

23. A force of 40 N accelerates a 5.0-kg block at 6.0 m/s2 along a horizontal surface.
a. How large is the frictional force?
b. What is the coefficient of friction?


6.3 Application of Vectors Read pp. 123-126 Questions #31, 35 (p. 131)

31. A street lamp weighs 150 N. It is supported equally by two wires that form an angle of 120° with each other.
a. What is the tension of each of these wires?
b. If the angle between the wires is reduced to 90.0°, what new force does each wire exert?

35. You slide a 325-N trunk up a 20.0° inclined plane with a constant velocity by exerting a force of 211 N parallel to the inclined plane.
a. What is the component of the trunk’s weight parallel to the plane?
b. What is the sum of your applied force, friction, and the parallel component of the trunk’s weight? Why?
c. What is the size and direction of the friction force?
d. What is the coefficient of friction?

Passing the baton to benofschool.

Shelly and erict, you guys forgot to label your labels on your previous scribe posts. ;)

Physics 09/19/09

Today in class we worked on our calculations for our friction and forces lab. A brief summary of our calculations are trying to find weight force, normal force, parallel force, horizontal force, and the coefficient of friction from our 9 trials of the block in our lab.

Continued...

Oh and we recieved 4 dynamics worksheets and reviews for the test on wednesday.

Tony scribes next..

18th of September

In today's class we started off with a recap on how to do the lab that started today. This lab was about the coefficient of sliding friction. This lab required an inclined plane, wooden block, pulley attachment on the plane, sandpaper, a set of weights, a string and a scale.

At first we did 3 trials on just the sliding motion of the block on the inclined plane. The trials required you to adjust the incline on the plane so the block would slide down the plane at constant velocity. Trial 1 required you to slide the block down with the widest part face down, trial 2 required sliding the block with the narrow side down, and trial 3 required you to slide the block down with sandpaper on the bottom of it. All these angles should have varied, but trial 1 and 2 should be pretty close.

The second part of the lab required us to try to slide the block up the incline, by adding weights to the string which is attached to the pulley which is then attached to the block. The angle is already given and weight must be added in order to pull the block up the incline. The inclines varied from 5 degrees to 55 degrees, and obviously more weight was needed with every increase of the incline. This was pretty much all we did for our lab, but tomorrow time will be given if it is needed.

In the back of the booklet we were given a couple calculations and questions that need to be done, and if you're done your lab I suggest you get started on it.

For homework we were asked to finish our chapter 5 study review, so get it done. The next scribe will be Dana.

That is all. -Francis

Dynamics September 17 2008

Hey yall if yall missed today's class or you need to refresh your mind this is what happened.

First Ms. K put an overhead up that had to diagrams of incline planes. Ms K then handed everyone out a transparency work sheet called: Forces On An Incline Plane. She also handed out another piece of paper but this time it was pink and it was called: Normal Forces, Friction, And The Incline Plane.


Ms K then went off to the office so that she could run off some more copies of the sheets so everyone can have one. When she came back we then corrected the Transparency Worksheet that she had handed out earlier. The answers are below.

1. What do you call the process of finding the magnitude of F_v?
Vector Resolution

2. Describe the relationship between F, F_v, and F_h?
F, = single Force
F_v, = Y Component.
F_h, = X component.
F_v is perpendicular to f_h

3. If F_h were negative, how would the diagram appear different?
F_h would point to the left.

4.If you only know the values of F and F_h what equation could you use to find F_v?
You would use The Pythagorean Theorem other wise know as a² + b² = c²

5. If you increase the angle at which F acts to 40^o, how will the components be affected?
F_v would increase and, F_h would decrease

6. Compare the set of vectors F_v and F_h with the set F_║ and F_┴. What do they have in common?
F_v and F_h are both component vectors and are ┴ to one another.

7. What cause the force W? Explain the orientation of this force vector?
Gravity, the orientation of this force vector will go down.

8. If the angle of incline were decreased to 15^o, how would the components be affected?
The parallel would decrease and the perpendicular would increase.

9. if you only know the values of W and Ø, what equation could you use to find F_┴?
You would use cosØ = F_┴/W

10. if the inclined plane is a frictionless surface, what other forces beside those shown acts on the trunk?
Weight and normal force is excreted by the trunk going upwards.


After we correct part of the chapter 7 study guide. The answer are below

Mix and match
11. e
12. c
13. g
14. b
15. f
16. a
17. d

18.


19


21.
Moves At a constant velocity.


After we correct chapter 7 study guide Ms K. then handed out two more pieces of paper one was a review worksheet and the other was a lab worksheet called: Coefficient of Sliding Friction. Tomorrow class will be a lab



Well yall that's all that we did in class hope this scribe post was useful the Next scribe will be Francis

Rguy/Richard out

Tuesday, September 16 2008

HELLO EVERYONE (:



For today's class, we started off by getting our Acceleration Test back. We were to correct them and hand them back again for marks. We then went over the first page of Chapter 7 Study Guide booklet and the answers were uploaded by Ms. K along with some notes about Inclined Planes. We were given the rest of the class to work on the rest of the Chapter 7 booklet, we were also told read pages 168- 179 on Normal Force and Friction (Duck book).

Also, a reminder that the Dynamics worksheet is due tomorrow, and thats pretty much it.



Oh, and the next scribe is RICHARD :)

Ch.7 Study Guide & Inclined Planes

Inclinedplane

View SlideShare document or Upload your own.

Monday, September 15, 2008

Hola Everyone!

Since no one wants to blog, I'll volunteer :)

So in today's class we started our Dynamics Unit.
We got a booklet and were given 4 problems to solve (found on page 5.)

Here are the answers:

1. a) No, the object cannot be in equilibrium because there is a force acting on it causing to accelerate.
b) No, the object cannot be in equilibrium because the sum of the two forces is not zero.
c) Yes, the object can be in equilibrium by having the 2 forces equal and opposite in direction (Fnet=0.)

2)

3)


4)


There was also the other sheet that we went over in class. Here are the answers for
Concept-Development Practice Page 4-1. Chapter 4: Newton's Second Law - Force and Acceleration:



Then we were given a booklet on Chapter 7 Study Guide, finish the first page (Section 7.1: Forces in Two Dimensions) and the other sheet Grade 12 Physics: Dynamics for tomorrow's class.

That's all adios, see you aaall tomorrow :)

Ohh yeaaaah, how can I forget?
the next LUCKY blogger is: christine d.
sorry tin, have fun though :D

FRIDAY'S TEST

hey class, today's class wasn't so bad at all...
we did a test then Ms. k hand out two sheets to work on this weekend.
Have a great weekend all of you.

Thursday's Class

Hey, this is Eric and I'm today's scribe.

We didn't do much today since we had a substitute. We pretty much worked on 2 new worksheets the entire class: one of those Study Guide assignments and some Relative Motion Problems. Near then we just corrected the two sheets near the end of the class.

Here are the answers:

Study Guide

21. A
22. C
23. D
24. A, B, C, D
25. B
26. D

Next sheet...

Relative Motion Problems

1. A) 10.5 m/s
B) 6.5 m/s

2. 36.9°

3. A) 20.6 m/s
B) 5.5 seconds
C) 25 meters

4. 165 m/s at 40° N of W

5. 240 m/s at 20° N of E

6. 34 m/s at 33° N of E

7. 147.4 km/h at 61.3° N of W

Those should be the correct answers, if they're not, you can all blame Richard.
That's it, and don't forget, we have a test tomorrow!

Next scribe can be...Zeph!

Relative Velocities Cont'd

So on with my second scribe post. ["Coincidentally" I was chosen by both previous scribes from Calculus and Physics to be the next scribe... I know, right?] I'll do my best as I kind of hurt my back in football practice and can barely sit right now, as I should be laying down in bed right now >=/.


We started off correcting the worksheet from the previous class. I'll just post the answers and a little summary for questions that need elaboration, because honestly, my back is killing me, but I was pretty sure everyone was in class, so...

NOTE: Judging by the number of people [including me] getting different answers, it is important to DRAW THE DIAGRAM CORRECTLY. So read the word problem carefully.

Answers:

4)
26.5 Degrees East of North @ 167.7 km/h [Answer may be round up]
-This was accomplished by correctly sketching the diagram, calculating the angle using the Tangent law and the Pythagoras theorem.

5)
Max Speed: 5m/s
Min Speed : 1m/s
Max Speed direction : With the current
Min Speed diraction : Against the current

6)
57 Degrees North of West @ 17m/s. [Note: the diagram is not a right angle triangle.]

7)
31.9 km/h
-If your not a "math" type person, you can just draw the diagram to scale (1cm = 10 km) and then from there use a protractor and trigonometric laws to find the angle to make a full triangle and then just measure the unmeasured line.

Following that, we were issued three more questions by Ms.K, which were questions 39, 40, and 41, from the second worksheet she handed to us yesterday.

39)
A) Use the sine law to find the answer which is; 13.6 degrees east of south.
B) Use the Pythagoras theorem to find the missing side to find an answer of 33 km/h.
C) Use the time equation (t = d/v) to find the time [21/33] = 0.64 h. To convert to seconds, multiply by 3600 seconds, and divide by one hour to find that there are 2304 seconds in that instance.

40) For this question we have to find which route is shorter, so we draw two diagrams complying with the word problem. (sorry for no diagrams, I can't stay on too long as my back hurts just to sit)
So for the first diagram, in which you try to swim directly across. t = d/v -> 1000m/ 2.2m/s = 454s.

For the second diagram in which you swim against the current, first we have to find the missing side. So we just use the Pythagoras theorem to find the missing side (c^2 - a^2 = b^2) and we get 1.51 m/s. From there we can find out how long it would take. t=d/v -> 1000m / 1.51m/s = 662 seconds.

So we find that swimming directly across would save us 208 seconds of time.

41)22 degrees north of east @16.2 km/h

After that, she gave us a sheet to read over. I did. Did you?

That's all for today folks. Sorry I couldn't elaborate on the questions more but honestly, my back's gonna give out. Hopefully I feel better tomorrow x( Now for an ice bath...

Oh and before I forget...

The next scribe is ERICT

Day 2 September 9, 2008

Hello everyone, this is benofschool. We started off class with 5 minutes of finishing off last night's homework and went on to correcting them.
For the first question on the homework the answers are:

Maximum: 101.5 km/h
Minimum: 98.5 km/h

To get the answers we just add the velocities together. The plane is always moving in the north direction so it's velocity (100 km/h) is always positive. The person inside the plane walking the length of it has a varying velocity depending on his/her direction. If the person was walking toward the front of the plane, his velocity in reference (in the point of view of) the ground would be the maximum speed because we have to take into account the velocity of the plane. If the person was walking towards the back of the plane (southward) his velocity would be negative. So his minimum velocity would be less than the plane's velocity because he is moving in the opposite direction of the plane's movement.

The second question involves 2 cars, Car A and Car B, with velocities of 80 km/h and 45 km/h respectively. The first part of this question asks for car B's velocity in reference to Car A if Car A was behind. This is just a simple matter of subtracting Car A's velocity from Car B's giving us a negative result. This is because Car A's velocity is greater than Car B's so then Car A is catching up to it. The answer should be -35km/h for a) and 35km/h for b). The second part involves the 2 cars moving towards each other. Their velocity in reference to any one of them would be the sum of both of the velocities because each of them are moving at their own velocity but we have to take into account the velocity of the other car. The answers for c) and d) should be 125 km/h.

The third homework question was to find the velocity and direction that a boat must travel in order to reach the eastern shore. The direction can be determined by basic Trigonometric skills (SOHCAHTOA) while the velocity can be determined using Ol' Pythagorean's Theorem
(a² + b² = c²). The answer should be 28 km/h [20° S of E].

After that we also recieved another worksheet on Relative Velocities.
The answers for the first three questions on the worksheet are:
1. 6.0m/s
2. 0.73m/s
3. 2.0m/s against the boat

That's is all the things we did today. So homework is the rest of the questions on the new worksheet. MAKE SURE YOU SIGN UP FOR THE BLOG OR YOU WON'T GET THOSE SUPER EASY MARKS!!!!

The next scribe will be Rence

This is your local cuddle monster logging off.
=)

First post for the year

It has been four days of classes and finally we get started with the blog, after a few days of transferring in and out of class things have begun to settle down in school.

Around the first two days of classes we received two sheets of Grade 12 Physics Acceleration Assignment. (one sheet has 7 question and the other has 10) For those who have missed those days here are the answers:

Grade 12 Physics Acceleration Assignment (questions 1-7)
1. 200m
2. 5.5m/s
3. o.74m
4. 1.1x10 ^-3m/s or 0.0011m/s
5. 9.8m/s
6. 5.6s
7. 75m

Grade 12 Physics Acceleration Assignment (question 1-10)
1. 8s
2. 164m
3. 25.6m/s
4. 180m
5. a)











b)











6. a) 27m
b) 8m/s
7. a) -1.15m/s²
b) 7s
8. 150m
9. 62.5m
10. 1.05x10⁴

Now, for today's class we finished and corrected the study guide on Displacement During Constant Acceleration (sheet 4.2). Here are the answers to the blanks (in said order) for those who have missed the class.

First paragraph:
blank 1: d=1/2(Vi + Vf)t
blank 2: d
blank 3: Vf
blank 4: Vi
blank 5: t
blank 6: velocity-time

Second paragraph:
blank 1: d= Vit + 1/2 at²
blank 2: displacement
blank 3: constant
blank 4: displacement
blank 5: acceleration
blank 6: straight line
blank 7: half a parabola
blank 8: instant

Third paragraph:
blank 1: time
blank 2: Vf²= Vi² + 2ad
blank 3: displacement
blank 4: final velocity
blank 5: initial velocity
blank 6: acceleration

Forth Paragraph:
blank 1: Galileo
blank 2: acceleration
blank 3: mass
blank 4: air resistance
blank 5: g
blank 6: velocity
blank 7: acceleration
blank 8: -9.8m/s²
blank 9: a
blank 10: given
blank 11: unknown
blank 12: rewritten
blank 13: subsituted

After that we were to read from pages 95-102 in the Physic textbook (blue bind).

HOMEWORK: Questions 35, 36 and 37 on the printout
And tomorrow's scribe is..... *insert name here* (I forgot the name D= )

Scribe List

This is The Scribe List. Every possible scribe in our class is listed here. This list will be updated every day. If you see someone's name crossed off on this list then you CANNOT choose them as the scribe for the next class.


This post can be quickly accessed from the [Links] list over there on the right hand sidebar. Check here before you choose a scribe for tomorrow's class when it is your turn to do so.

Vieteran christine D Francis Dana

De Dieu

yonas