Exam Discussion!

[theshunpo]

Speaking of the locomotive question, what did you guys get for the tension in the coupling?

[xdtash]

Speaking of the locomotive question, what did you guys get for the tension in the coupling?

I got 4000N. I treated the coupling as kind of the 'thrust' of the two carriages, so a=0.2, and the two masses equal 20000. Multiply them together to get 4000.

[theshunpo]

I got 4000N. I treated the coupling as kind of the 'thrust' of the two carriages, so a=0.2, and the two masses equal 20000. Multiply them together to get 4000.

Yeah 4000N is what i got as well. I worked from the 2nd carriage first to find the tension between the 1st and the 2nd. Then proceeded to resolve forces on the second carriage and set it to ma.

[FSH7]

What did everyone else get for the graph of the modulated signal? It kinda threw me off because I've never seen one involving light pulses before.

[jumcakes]

What did everyone else get for the graph of the modulated signal? It kinda threw me off because I've never seen one involving light pulses before.

I think it looks like a tall column between t = 1 and 2, 3 and 4, and then a short column (just like the signal wave) between 5 and 6, all above the x-axis (since intensity is always non-negative), but again I'm not completely sure.

[rhys.oo]

was momentum elastic or inelastic 
how many marks was 1a and the first projectile motion question

[FSH7]

was momentum elastic or inelastic

Inelastic since KE was lost according to KE=1/2 mv^2

[d4m0]

Does no one have a copy of the physics exam? Strange because after the methods one, the solutions were put up almost straight away. How do people get their hands on the exams afterwards anyway?

They get given out to teachers, presumably for methods the people posting the solutions asked their old teachers for access to their copies, or something. Seems no one cares enough about physics to do it. Side note: you go to my old school :p

also I got what jumcakes did for the modulation question

[xdtash]

What did everyone else get for the graph of the modulated signal?

I left that one until the very end. I ended up just making it like an "addition of ordinates" that you learn in maths.

[theshunpo]

 
how many marks was 1a and the first projectile motion question

Question 1a) was the distance traveled question..i'm pretty sure that was 2 marks.

[FSH7]

was momentum elastic or inelastic 
how many marks was 1a and the first projectile motion question

If by the first projectile motion question you mean the cricket questions then I distinctly remember that both parts were worth 2 marks, each that is.

[rhys.oo]

for the circular motion question did people get a mass using a formula such as r3 / T2 = G.M / 4.ᴨ2
how many marks was that question

[xdtash]

for the circular motion question did people get a mass using a formula such as r3 / T2 = G.M / 4.ᴨ2

Yeah, I ended up getting like 1.something*10^31? Something around that

[chuck981996]

Does no one have a copy of the physics exam? Strange because after the methods one, the solutions were put up almost straight away. How do people get their hands on the exams afterwards anyway?

lol that's because I don't do methods. Teachers don't like to give you an exam that you just sat.

[FSH7]

Yeah, I ended up getting like 1.something*10^31? Something around that

Yes! I got 1.08 x 10^31.