James Ang:

suggested answer for discussion (due to lack of information on the actual question asked in the exam) is

1) When the air is released from the balloon, a forward force is produced in the direction opposite to the direction of air travel. So the balloon moves in a different direction which is opposite to the direction of air travel.

:

No one has the actual question? You interpret 'different direction' as opposite direction. hence Newtown 3rd law applies.
My 1st impression was it was going in different directions (note pural). Hence aerodynamics of asymmetrical drag force and propulsion is not along the line of the ballon's C.G applies, as it has indefinite shape, and it C.G is shifting all the time. In simple term, \"no fix\" shape of the ballon applies.

ChiefKiasu:

Yong HL:

I told my girl got ghost. She gave me the :roll: look.

Children these days don't believe in ghosts anymore lor. Anyway, have you ever wondered why balloons would fly the other way when air is released, but humans don't do that when they fart? Strange right? Maybe should be in next year's PSLE Science.

If there's no gravity , out in space. Your fart will definitely push you in the opposite direction without stopping. You be lost in space. Like what they show in the movie Gravity and The Martian. Little burst of air will propel the astronaut in one direction.

ammonite:

I hear that balloon question was only 1 mark. I doubt they are expecting aerodynamics for just 1 mark. I will hazard a guess that it was probably something about changing elastic force and having no fixed shape, working against gravitational force. These would be totally within syllabus and have been taught in many ways.

No fix shape, that's aerodynamic concept. Resulting in no symmetry of drag forces. That would be my answer too
If the setter intend no fix shape as the answer, then their are expectations is beyond p6.

jetsetter:

for every force there is an equal and opposite force

That is Newton's 3rd law of motion.

These are beyond p6.

Are they taught newton’s 3rd law of motion and aerodynamic for thr balloon question? Or is there a simpler explanation.

The spring question is tough. Seems like they are interview question for a mechanical engineer.

phtthp:

Thanks, Ninac


At first when I saw the Maths qn on light bulb, I thought it was a Science qn testing students on Light energy (Physics) concept, until I saw the calculations involved, then realised is Maths.

Is quite an \"out of the box\" qn, involving Physics (Science), in a Maths qn.

I guess those questions that uses flower pots for arrangment involves botany. :shock:

lee_yl:

Just curious, this light blub question resemble a MO type interval questions?

No.
Seen this type of question in P4 onwards till P6. Sometime, they use street lamps, flower pots. Sometime arrange in circle, square. Psle slightly tricky where they mentioned 3 sides only.

jetsetter:

Ender:

[quote=\"twin2003\"]Looking at the questions in the link, they don't look like MO questions... they just require the students to be careful in answering.

The video presentation? I agree they are not MO level questions.
Can someone post the MO questions?

There were MO questions?
Or just slightly challenging questions that require application of techniques already taught?

Light bulb one is \"MOish\" but it's not crazy tough. It's for 7-8 yo to solve.

A 12yo who reads the qn carefully can get \"585\" too.

The rest look reasonable compared to some of the tough qns you guys have been posting in AskQ.[/quote]From what I have seen posted here and on the video, nope. All are pretty standard PSLE level that any students who pratice alot with past year questions should be able to handle.

twin2003:

Looking at the questions in the link, they don't look like MO questions... they just require the students to be careful in answering.

The video presentation? I agree they are not MO level questions.
Can someone post the MO questions?

slmkhoo:

buds:

[quote=\"starlight1968sg\"]ME time today, planning to explore my new neighbourhood but ended up accompanying dd to polyclinic as she has a big mouth ulcer

Bonjela works for us.
Heals pretty quickly too.


It's a known brand of oral treatments aimed to relieve the pain of mouth ulcers and denture sores.

We find that Bonjela is quite ineffective. We use it if the ulcer is just about starting, but our go-to solution is the salt water or salt. If the ulcer is not really developed yet, drinking 凉茶 helps too.[/quote]For me is Oracort E. Only can be prescribe by doctor as it contains a little amount of steroid. NExt time for ulcer, ask the doc for Oracort E.
Note: Read that it's it not suitable for infection type of ulcer.

http://www.apotheca.com.sg/wp-content/uploads/2015/08/Oracort-E-5mg.jpg\">