VCE Physics Question Thread!

[Orson]

I wish you all the best for tomorrow. It's been a good year of Physics, lets show VCAA what we know!

Thanks for all the help over the year, and especially these last few weeks. See you all on the other side...

[Orson]

I was doing VCAA 2014 Q5a. I used this:

g = (G*M)/(R^2), g = 10m/s^2

Why is this wrong?

Thanks!

[byCrypt]

Is it too late to start studying for physics?

[zsteve]

Just checking this: for AC calculations (power, energy, etc) always use RMS values - yes?

[Adequace]

Is it too late to start studying for physics?

Dunno, just ask pi.

(He apparently studied the night before the physics exam only  ).

[odeaa]

Is it too late to start studying for physics?

Dunno, just ask pi.

(He apparently studied the night before the physics exam only  ).

beat me to it ahah

[Orson]

deltaX is the change of length of a spring right? Could someone have a look at VCAA 2014 2b? They ask for the extension, but the answer is the extension + length.

deltaX = 0.4, not 0.8

[byCrypt]

deltaX is the change of length of a spring right? Could someone have a look at VCAA 2014 2b? They ask for the extension, but the answer is the extension + length.

deltaX = 0.4, not 0.8

I think the answer is extension, as they equated the gravitational potential energy at the top (bottom of spring at unstretched length) to the spring potential energy at the bottom. The h in mgh is equal to the x in 1/2kx^2. So I believe the extension is 0.8m.

[cooldude123]

I was doing VCAA 2014 Q5a. I used this:

g = (G*M)/(R^2), g = 10m/s^2

g=10m/s^2 only applies to gravity at the Earth's surface (not to a planet orbiting a star). The value for g would be different.

You need to use Kepler's Laws and transpose for m.

[Orson]

g=10m/s^2 only applies to gravity at the Earth's surface (not to a planet orbiting a star). The value for g would be different.

You need to use Kepler's Laws and transpose for m.

Cheers dude. You're pretty cool, you know that?

[SayJay]

http://www.itute.com/wp-content/uploads/2013-2016-vcaa-physics-sample-exam-solutions.pdf

In section A, question 8 (b+c) I've calculated the period value to be 1.56 * 10^4 s, and yet itute solutions say 1.53 * 10^4 s? I've used that value from 8(b) in 8(c) when finding the velocity, so I got 5.44 * 10^3 m/s (itute says 5.54 * 10^3 m/s).

[SayJay]

Just checking this: for AC calculations (power, energy, etc) always use RMS values - yes?

Yes, unless stated otherwise.

[paper-back]

What is RMS exactly?

[Orson]

What is RMS exactly?

Root Mean Square...

[schooliskool]

Is it too late to start studying for physics?

Is it too late now or na