Physics Exercise 2.10

This is for those who didn't manage to jot down the questions in class earlier today. Solve the questions in your exercise books.

1. A crane lifts a load of 5000N through a vertical distance of 12m from a ship to the ground in 20s. Calculate the average power of the crane. [ Unit of Energy: Joule (J) ]

2. A rock of mass 4.5kg falls from a height of 14m to the ground. Calculate the loss of potential energy when the rock is 5m above the ground.

3. An electric motor lifts a box of mass 5.0kg to a height of 18m in 5s. Calculate the power of the motor.

4. A lift in a building can carry 15 people through a height of 10m in 10 seconds. The total mass of the lift and its passengers is 1500kg. Calculate the power of the lift.

5. A fat man of mass 100kg and a thin man of mass 50kg both ran up a flight of stairs at a height of 12m. Both the men took 10s to complete the task. Calculate the power generated by each man.

6. The graph in figure below shows the relationship between force, F and the spring extension, x.

Calculate the work done to stretch the spring from 8cm to 12cm.

7. An electric motor of a crane rated 500W can lift a load of 450N vertically through a height of 8m in 10s. Calculate the efficiency of the motor.

*Refer to your notebook if you're stuck at any question.

Shifted - Assessment 2

Just a little announcement in case you didn't notice the announcement on the board earlier. Tomorrow the Physics and Add Maths test is shifted to after recess. According to the schedule, it was suppose to be before recess but Mr Shukur just told me this morning that it was shifted to after recess. So, I don't really know which one to follow either. So, I'd suggest you just bring all the books required in our original class timetable. Add Maths and Physics lessons is on the same day too. So, it shouldn't be a problem.

That should sum it up.

Finally..... Some update

Referring to the above title, it is informed that tomorrow, June 24th 2009, boys will be having their PK.

For the girls, I think you'll be having PJ tomorrow if i'm not mistaken. At the very least, that was what I have heard.

.......Reminders.......
1. Physics ticker-tape experiment report in your Experiment book. If you haven't done yet, finish it.
2. Bring your RM25 for the t-shirt ASAP. The time taken to receive your t-shirt depends on everyone's said payment. Hypothesis is accepted. LOL
3. Those who haven't paid your toilet fees, please do so ASAP.
4. If you have any H1N1 symptoms, please get yourself examined. Stay home if you feel something's wrong with your body system. The virus can spread really fast so, be cautious of your surrounding.

p/s: Sincerest apologies to those whom I wasn't able to wish you your birthdays. I currently aren't able to use a constant internet connection, so I can only post once in a while. Really sorry for the inconvenience.

I'm out of ideas for the title....~~~ sienz

Haha, it's been quite some time since the last post, eh? I've been kinda busy with the new layout. Just a few reminders and notifications....

Biology

We'll be conducting an experiment on Wednesday. The experiment revolves around the concentration of solutions, I think. So, I'll advise you to bring a potato for yourself. Although you'll be in a group of 4, it'd be better if you just bring one just in case other group members didn't bring their share of potatoes. Just make sure the potato isn't too small. We need to observe what would happen to it. 

Ah, I just remembered there were still some of those who didn't get their Paper 3 exercises. The one on the erythrocytes.So if you want the exercise, come and see me. I still have a few more copies with me. And thats all for Bio.

Secondly is Physics

Yah, physics PEKA. Tomorrow's the deadline. Submit your PEKA tomorrow. Don't really have much to say about this. So, that's it lah. Oh yah, there's still another thing. Prepare a report on your rocket.

Next is Results Slip

If your name is listed here, please bring your Results Slip tomorrow.

a) Alvin

b) Veno

c) Vinod

d) Arina

Yeah, bring it tomorrow, kay? I only need 4 more. I've been holding 33 of these since the last 2 or 3 weeks, so please help me get rid of the extra load in my bag. XD

Chemistry

Those 10-12 pupils who haven't pass up your exercise book, please do so. The deadline was weeks ago. Chances had been given. Just don't take things for granted. What's the point of giving chances if you don't try your best to use it to the fullest? Ah and yes, summarise the notes on chemistry located below. Or just use this link if you're lazy.

Bahasa

Haha. Pass up your Karangan book tomorrow. The essay is about the Rumahku Syurgaku letter, if i'm not mistaken. So, finish it up and I'll collect it first thing tomorrow.

Add Maths

We'll be having extra class this Friday until 12:50 pm. So, inform whoever is picking you up that you'll be a bit late.

PJ (For boys)

Directed to all 4M/J boys. We'll be having PJ on Wednesday to finish up the SEGAK test. There'll be a bit of push-ups and sit-ups, i think. So, best prepare yourself if you feel like impressing some anonymous person. Isn't that right, Nic?

Science & Maths Society

The S&M society is organizing Explorace as part of their participation in the Academic Month. The race is open to all morning-session pupils. A fee of RM4 will be charged on each group and each must have only 4 group members. No more, no less than that. Further information can be obtained at the S&M notice board located on the ground floor of Block B. Or if you don't like walking to the board, you can always have the walking board, Parri, come to you instead. XD

I don't think I want to bring up anything about the Sport's Day. So, that's the end of the first post for the new layout and that's all until the next post comes, I guess.

3, 2, 1, Launch

Tomorrow is your rocket-launching day. Get your rocket and parachute ready and be prepared for inconvenient conditions. May the wind be on our side.

Physics PEKA - Submit by Friday. Latest by next Tuesday.

New Layout Development

The new layout might take some time to be applied here since the layout that you saw had an error regarding the banner. So, maybe I'll try to learn the XML code and rebuild the layout.The earliest the layout would be up is by the mid-term holidays. Anyone who have experience and advanced knowledge on XML codes, please assist me. I'm just modifying any part I can understand.

Sports Day is coming soon. For those who took part in competitions and taekwondo demo, you'd better prepare yourself well. There's a full rehearsal tomorrow too so, do your best. XD

~I dream of sleeping~

Physics Ex 2.4 Compiled

I compiled the exercise so you won't have to scroll down to find the first part of the work. So, there it is lah.

Excercise 2.4

1(a) A lorry managed to travel a distance of 6km in the last 15 min. Upon nearing a traffic light, the lorry driver stepped on his brakes to stop his lorry. The speed of the lorry decreased uniformly and came to a halt after 3 seconds. Calculate
(i) the velocity of the lorry in the initial 15 minutes
(ii) the initial velocity of the lorry
(iii) the deceleration of the lorry

(b) A steel ball of mass 1 kg is dropped vertically from a table as shown in Figure 1(which habib will post later). A bucket of sand is put beside the table so that the steel ball can drop into it.

If the steel ball took 0.5 s to reach the bucket of sand, calculate:

i ) The velocity of the stell ball when it hit the stone.

ii) The height of the table.

iii) The deceleration of the stell ball if it managed to sink 10cm into the sand.

(consider: g = 10 m/s^2)

Okay, that's all for your exercise. Now just read page 8 in your Practical Book. Read, understand, conceptualize and repeat.

MON(DAY) = HO^LI(DAY)

As most you would have known, Monday is a holiday. Unless you're going to the Maulidur Rasul celebrations, that is. I really have nothing else to say so, I'll just get to the point.

1. Pn Wong ask us to print this http://smkbsa.net/english/CHECKLIST.htm. Please print it and paste it... somewhere? I forgot where we should paste it, DX. Nevermind that, the main thing is that you must get a hardcopy of it.

2. Anyone who's interested in 'Pidato' or 'Bahas ala Parlimen' or 'Mendeklamasikan Sajak', please inform me by.... next week.

3. Please bring a 10sen coin to school on Tuesday. I need to photostat your Physics exersice. It's just one page. Don't expect me to be doing charity work. I did that once, and i'm not planning to do it again anytime soon.

4. UPDATE: You can't use 'Di samping itu,' as penanda wacana anymore. It's not accepted because 'itu' refer to something abstract. It can still be used in a normal sentence, though. But the phrase must be followed by a concrete object. Eg. ... di samping sebuah rumah... In this case, the house is the concrete object. For more information and updates, please inquire Pn Wee.

So, that should be all. Anyone who needs some notes to be posted, please request it. I know i've mentioned this around 8 times, but please request if you ever need any. Don't come to school and complain to me i'm not posting any notes up here like Richard did. (I'll only post unrequested if more than 7 students is not in the class) If you need any, please request through the inquiries option. Don't ask for solutions or answers of a certain assignment, maybe i'll post a guide but never an answer. So, don't ask for answers.

: 2.1 Linear Motion : Notices : Homeworks

Apologies for the late post. As my excuse for the lateness is currently irrelevant, I shan't explain myself. Today's homework shall be posted below; prefects, please take note. Right below is today's physics notes and below the notes are the exercises.

Thursday<---->Feb 5, 2009

Chapter 2: Forces and Motion

2.1 Linear Motion

Distance and Displacement

1. Distance is a scalar quantity whereas displacement is a vector quantity.

2. Displacement is measured by the length of a s

traight line joining in a specific direction.

3. Displacement is the distance travelled in a specific direction.

*Please draw*

Example 1

If a boy takes 10s to finish each of the following paths AB. Find the total distance travelled, and the displacement in each case.

*Please draw*

Total distance travelled

= 2 + 4 + 6 + 8 + 8

= 28m

Displacement

=Shortest distance A and B

= (4 + 8) m

= 12m

*Jot these down on the exercise book*

Thursday<---->Feb 5, 2009

Quiz 1

1. Convert   to metre in standard form.

Solution

2. Convert  to SI unit and in standard form.

Solution

: Homeworks :

1. Add Mathematics - text book pg 66. Practice 1: b, c, e, f.

2. BM - work book pg 40. Find 6 evident points (isi tersurat) and follow the guide on pg 41. Write a complete rumusan.

: Notices : 

1. Please submit your Tatabahasa (and KOMSAS if you haven't submit earlier) to Pn Wee.

2. Complete the rumusan by tomorrow unless you wish to have another round of lecture. As for Ashwin and Ethan, please complete your previous work.

3. Attention to:

a) Alvin

b) Akhilash

c) Ameer

d) Vinod

Please bring RM 3 tomorrow for the photo and pass it to me.

4. Those who have not submitted the SPBT forms and PIBG meeting verification forms, please do so tomorrow.

5. AJK's, verify your presence tomorrow. Those willing to help are also welcome.

6. Since my instructions about the voting system was ignored. I'll just stick to the current reading corner table cloth. Coincidentally, it got the highest vote too.

7. Those in charge of the timetable, birthday list, etc. , please complete it tomorrow. Unless your work is very unusual and may take some time, then Tuesday would be your deadline. If not possible, please come and see me and update me on the progress.

Last but not least, 

Happy belated Birthday to Sugumaran.

:1.5 Scientific Investigations (Physics): Misc. Notices:

As I have mentioned in the previous post, the 1.5 Scientific Investigations notes dated on Feb 2, 2009; Monday. Deepest thanks goes to Hilman for providing the neatly-written notes.

Tuesday <----> Feb 3, 2009

1.5 Scientific Investigations

The process of scientific investigation

a) Inference

b) Hypothesis

c) Aim

d) Variable + Operational Definition

e) Apparatus

f) Procedure

g) Observation

h) Analysis

i) Discussion

j) Conclusion

A) Inference

1. Inference is an early conclusion to what is observed. The conclusion can be correct or incorrect.

2. Example: When the length of a simple pendulum increases, the period oscillation also increases.

B) Hypothesis

1. Making a smart guess or tentative explanation about the phenomenon based on the observation.

2. Example: The longer the length of a simple pendulum, the longer will the period of oscillation be.

C) Aim

1. When an experiment is carried out, an aim has to be stated so that all the investigating effort is centred on the main subject.

2. Example: To find the relationship between the length of a simple pendulum and the square of its period oscillation.

D) Variable

1. A variable is a factor that affects the results of an experiment.

- Manipulated variable: A primary variable which causes other secondary variables to change.

- Responding variable: A secondary variable which changes in response to the change in the manipulated variable.

- Fixed variable: A variable which is always constant throughout the experiment.

2. Example: a) Manipulated variable: Length

<------------>b) Responding variable: Period, T

<------------>c) Fixed variable: Mass of the pendulum bob

E) Operational definition

1. Operational definition is required to define the manipulated and responding variable to be measured.

2. Example: Measure the length of a simple pendulum using a metre ruler. Measure the period of oscillation by using a stopwatch.

F) Apparatus

1. Needed to be listed according to its specifications so as to ensure the success of the experiment.

2. Example: Retort stand, pendulum bob, string, metre ruler, stopwatch.

G) Procedure

1. The sequence of action or operation in order to carry out the experiment according to the instructions given.

2) Example:

i- Set up the apparatus as shown in Figure 1.

ii- The description of procedure must be in past passive tense, for instance:

"Measure the period of oscillation of the simple pemdulum using a stopwatch" must be written as "The period of oscillation of the simple pendulum was measured by using a stopwatch".

H) Observation

1. The listing and tabulation of all data obtained in the experiment.

2. Example:

________________________

|Length of string (cm)|   T1  |   T2  |

|_________________________|

|<----40.0------------->| 25.5 | 25.1 |

|<----50.0------------->| 28.1 | 28.2 |

________________________

* Deepest regrets for any inconvenience caused.

I) Analysis

1. Analysis of data can be carried out by plotting graph, followed by the interpretation of graph or calculation to obtain the required value.

2. Various precautions in plotting graph taken into consideration.

- All axes must be labelled.

- The graph must be labelled by a header.

- The manipulated variable should be plotted on the x-axis while the responding variable should be plotted on the y-axis.

J) Discussion

1. Discussion need to be stated to find out whether the results obtained support the stated hypothesis. Precautions of the experiment can be suggested to overcome the weakness, to reduce experimental errors or to improve the results of the experiment.

2. Example: In order to improve the experimental results, make sure that the amplitude of oscillation of the simple pendulum oscillates in a vertical plane only.

K) Conclusion

1. A conclusion is stated concerning the results of the experiment.

2. By comparing with the aim stated, this will be determine whether the hypothesis is accepted or not.

3. Example: The length of a simple pendulum is directly proportional to the square of the period of oscillations.

____________________________________________________

:::Notices:::

1. Those who have yet to pay the RM3 for the photo, please do so.

The 4 who haven't pay up yet are:

a) Akhilash

b) Alvin

c) Ameer

d) Vinod

2. Please bring the SPBT verification form(s) as well as the PIBG meeting form tomorrow.

3. Finish up all your BM homework (Tatabahasa & KOMSAS) by tomorrow. Pass it to me after you're done. If you wish to send it later, do so at your own risk.

4. Please bring a book tomorrow for the reading corner. All books are accepted except those rated 18+ and/or contain obscene images.

p/s: To AJK's.

Arina---> Reminder: Please bring the batik cloth tomorrow.

---> Please update me about the situation of the notice boards. Those boards need to filled by this week. I'm planning to finish it on Friday so I'll ask Mr Shukur if he's free on that particular day. Please inform me of your presence ASAP.