KiasuParents - Parenting in Singapore

this question is from 'all about physics' o level theory workbook :
action of 3 forces for 2-dimensional cases & components of force



thank you so much for explaining the concept

Here is an answer to Mental of Steel's question. I saw this type of question from no less than 5 different schools on either CA1 or SA1 for Sec 3 in 2015 and I expect it to be a popular exam question for Sec 3 in 2016. We have these kinds of questions in our tuition center worksheets because we are constantly updating with the recent school questions.

Here is the question:


The most important thing to realize about this question is that you cannot use the original drawing for a scale diagram. The reason why is that the 500N force is in a rope that is longer than the rope containing the 866N force. That's possible by the way. Just because I have a shorter rope doesn't mean that the tension, or the force within that rope, has to be less. It could be more.

So we must redraw the problem and we redraw using the tip to tail method of vector addition. You use a protractor. Take a scale of say 1cm = 100N. First, draw the 866N force being 8.7 cm long with a ruler and use a protractor to draw it at the correct angle. Then start at the tip of the 866N force, draw a horizontal line (dotted red line), measure the correct angle and draw the 500N force as 5.0 cm. Then you draw the resultant force in black as shown. Measure it with your ruler and it should come out to about 10.0 cm. This is 1000N according to our scale. That resultant upward force is also equal to the weight downward. The resultant force is acting directly opposite the weight, so there is no angle with respect to the vertical, it is exactly vertical.



So the answers are:
Scale: 1cm = 100N
Magnitude of Resultant Force: 1000N
Direction of Resultant Force: Exactly Vertical
Weight: 1000N

So then you can verify your answer with trigonometry. There are two ways to verify the answer. One using the trig components and the second if you can see the resultant is the hypotenuse of a right triangle. So for those of us who may not have the artistic skills of Leonardo Da Vinci, we can make sure the darn drawing comes out right by doing the side calculation. So your resultant vector should come out to about 10.0 cm.

Hi, can anyone who is familiar with the Singaporean Physics O level, advise if the new Physics Higher GCSE, done here in the UK, is easier or harder than your o level. Please look at the Specimen Higher Paper only. The URL is below:

http://www.aqa.org.uk/subjects/science/ ... -resources

Anyone, can you respond to my previous post as I am trying to work out if my ds can rehearse SG Olevel papers for the the new UK GCSE

Hi, my daughter is in Sec 3 and taking pure physics. She needs a tutor to go thru' the physics from beginning of the year onwards as she is lost. Pls recommend if you know of any good physics tutors. We are staying in the west.

MTIA

Newtandcucumber wrote:Hi, can anyone who is familiar with the Singaporean Physics O level, advise if the new Physics Higher GCSE, done here in the UK, is easier or harder than your o level. Please look at the Specimen Higher Paper only. The URL is below:

http://www.aqa.org.uk/subjects/science/ ... -resources

The topics covered in the Higher GCSE paper are in some cases different than what is found on the Singapore O'Level. So if you are practicing the Singapore O'Level to prepare for this paper it will be inadequate preparation. One example is the question on the expansion of the Universe, which is not covered in the O'Level. Another example is nuclear physics and the radioactive decay questions. Also, most of the questions in the Higher GCSE paper are asking students to explain their reasoning and it is testing the ability of students to draw on their general knowledge to answer the questions. It contains questions of a different style than commonly seen on the Singapore O'Level (although the O'Level is trending in this direction in the last couple years). This UK paper is more in the style of the IB exam, although not as hard as the IB exam. So practicing the Singapore O'Level is OK for some of your preparation, because there is overlap, but try to get a hold of UK papers more in the style of this exam to complete your preparation.

Overall I like this test. We use some questions of this style in our classes to prepare Singapore students for the O'Level because as I mentioned, the O'Level is trending in this direction. It also helps Singapore students to get exposed to different styles of questions and makes them more flexible as exam takers. But sometimes it takes a lot of explanation to the students to help them with the thought processes needed to arrive at the answers.

Thank you Dr Daniel. My son will be the second cohort to do this paper. Currently, he is UK Y8 ( age 12 to 13 cohort) and he has covered a lot of content that I covered in my JMB O level of 1982. You say it is like the IB, but not as hard as IB. What qualification from IB suite is similar to GCSE.

Personally, I felt more comfortable with the SG Paper as it asked most questions to a similar level to my JMB o level.

I am still not sure as what to make of the AQA GCSE. In some ways, it is easier and some not. In the UK, we have moved away from individual pure sciences to individual applied sciences. Off course, the new 9-1 grading will make it worse.

FYI, here is the URL to the new A Level in Physics he will sit two years later. I remember doing options in my 1984 Physics Alevels. I did Medical Physics and Electronics. Strangely, they still do options at A Level.

http://www.aqa.org.uk/subjects/science/ ... -resources

chubby08 wrote:

krz wrote:Dear all.
My dd is in temasek jc, ip yr 3.
She needs help in physics.
Is anyone giving / intending to give, tuition ?
Or know of anyone who is doing it ?
Really need some help , n references.
Thank in advance.

I have PM you.please check.

Hi, can anyone recommend a good Physics Teacher for O level Physics? Thanks

Please help with this question. Thank you.