Recent content by fwong

What do you mean by "thoery"? Many students, and even teachers, think the description in words is the "theory". This is complete non-sense. Theory is the explanation and derivation of equations. In the current syllabus, there is hardly any theory at all. The majority of formulas are taken...

Who said you can buy your degree there??? I work there. The contract signed by Macquarie City (Navitas) and Macquarie University is that all teaching has to be exactly the same as in the university. In particular, exam paper is at least as hard as those in the university. Exams are...

ONe simple answer: YES. Almost everyone (teachers, textbooks) says sling shot is a process whereby a space probe **gains** energy and momentum from a *moving* planet. But there is another version of slingshot when purposely the space probe has to be slowed down, and thereby losing energy to a...

Hint: Think about the flow of (positive) current in a circuit driven by a battery. Outside the battery, current flows from + terminal to negative terminal, as we were taught. But look at what happens inside the battery, (positive) current flows from - to + terminal. Got it? Teacher

This is silly. Celestrial mecahnics is UNlike driving a car where you can stop and turn around. This is impossible even in theory. The Apollo 13 essentially had no option. Period.

No. g-"force" is the ratio of reaction force divided by "true" force mg.

"Just find force ..." Which force? Gravity? Applied force? Net force? Or reaction force? A little knowledge is a dangerous thing!

The HSC question from BoS was wrong. The person who set this question didn't know what he was saying. Some students a few years back said that this question was cancelled in the HSC marking. Trust me. I am a teacher. I have confirmed that this question does not make sense with Dr Joe...

No, if the MM experiment could measure the Earth's velcioty in ether, it means ether existed. In other words, the existence of ether is tied closely with the relative velocity of Earth in the MM experiment.

Neither is correct. Compression and rarefaction are the midpoints between compression and rarefction, depending when the particles move towards the point or away from the point Frederick

von Braun most important contribution was the design of the Saturn V rocket, which sent Americans to the moon. The Russians failed to successfully launch a similar rocket and they eventually gave up the moon race. Although retired, Saturn V remained the largest rocket Man has built so far.

It is a consequence of EM Theory (way beyond high-school level) that whenever charges are *accelerated* then EM waves will be given out. This is exactly how all transmitters work: mobile phones, radio or TV stations. In a high-frequency AC circuit, electrons oscillate to-and-fro, hence...