Exam Discussion

[caluuu]

fml
somehow managed to divide by wrong number in power q . lost 1- 2 marks at least fml

same i got them both = 0.1 :/

[WhoTookMyUsername]

when's the earliest we can order SoM?

fml
somehow managed to divide by wrong number in power q . lost 1- 2 marks at least fml

same i got them both = 0.1 :/

i got one of them right
the otherone i divided by the wrong number somehow, need to see a copy of the exam

[max payne]

i was proud to see drawing of the circuit again! how ever too many explaining questions TT whoever thought the first question would be spring related-.- but it was really easy. Did everyone get B as the answer in order for the ball to be stationary?

Yes, inorder to be stationary the forces must be in equilibrium therfore the horizontal forces must be balanced as well as the vertical forces. B was the only one where the horizontal and vertical componants of the forces could be balanced.
Thats sort of what i wrote... I was a bit surprised by that question since it seemed like it belonged in the M&S section.

[yellowsone31]

I added the frictional forces to find T1 i think it was 800N..

Yay me too!

[VCE_2012]

TOO MUCH EXPLANATION! I couldn't explain why diode 1 had the higher fraction of electrical energy converted to light energy and also Q7 of StrucMat confused me a bit for some reason

For the diode explanation your referring to I applied the percentage efficiency formula for each diode. In the end Diode 1 was more efficient (75%). %(efficiency)=(practical power dissipated)/(theoretical power dissipation)x100.
 

[rife168]

I don't think the reaction force is the force on the earth because it is connecting to the string so there is no way it could be that...

Yeah, reaction force of the earth moving towards the ball would only be if the ball were free falling?

Just because the ball isn't falling doesn't mean there isn't a force present, it just happens that the tension in the string is equal to the weight force.

Action-Reaction forces only ever act on two different bodies. The question explicitly stated that the action force is the weight (gravitational force by Earth). If you stated that the tension was the reaction force, then I believe it would be incorrect as both the tension and weight force act on the sphere.

[micklepicklez]

if i wrote D1 with no explanation, would I at least get 1 mark ?

[max payne]

TOO MUCH EXPLANATION! I couldn't explain why diode 1 had the higher fraction of electrical energy converted to light energy and also Q7 of StrucMat confused me a bit for some reason

For the diode explanation your referring to I applied the percentage efficiency formula for each diode. In the end Diode 1 was more efficient (75%). %(efficiency)=(practical power dissipated)/(theoretical power dissipation)x100.
 

Thats whati got except i got 3/4 and 2/3 since it asked for fractions not percentages. For the draw a circuit did you get 2000 ohms resistor and the V out on the Light dependant thingi since its resistance increases with decreasing light intensity?

[VCE_2012]

TOO MUCH EXPLANATION! I couldn't explain why diode 1 had the higher fraction of electrical energy converted to light energy and also Q7 of StrucMat confused me a bit for some reason

For the diode explanation your referring to I applied the percentage efficiency formula for each diode. In the end Diode 1 was more efficient (75%). %(efficiency)=(practical power dissipated)/(theoretical power dissipation)x100.
 

Thats whati got except i got 3/4 and 2/3 since it asked for fractions not percentages. For the draw a circuit did you get 2000 ohms resistor and the V out on the Light dependant thingi since its resistance increases with decreasing light intensity?

Yes. About my response to that diode question; it's still acceptable do you think?

[mikesguns]

Yes it was 2000 ohms, I did 3000*4/6=1500 lol

[max payne]

TOO MUCH EXPLANATION! I couldn't explain why diode 1 had the higher fraction of electrical energy converted to light energy and also Q7 of StrucMat confused me a bit for some reason

For the diode explanation your referring to I applied the percentage efficiency formula for each diode. In the end Diode 1 was more efficient (75%). %(efficiency)=(practical power dissipated)/(theoretical power dissipation)x100.
 

Thats whati got except i got 3/4 and 2/3 since it asked for fractions not percentages. For the draw a circuit did you get 2000 ohms resistor and the V out on the Light dependant thingi since its resistance increases with decreasing light intensity?

Yes. About my response to that diode question; it's still acceptable do you think?

well they specifically said fractions so i cant imagine them taking marks off. So it might be one of those questions where both would be accepted

[fisa2001]

Surprised that no one has used the range formula in order to find the velocity of the projectile motion. And I thought hookes law only has one formula which is f = kx :/. Left like 6 questions thanks to my school being indie and picking relativity as detailed study. Mums pretty pissed about leaving 6 questions... sigh

[JoshReid]

For the draw a circuit did you get 2000 ohms resistor and the V out on the Light dependant thingi since its resistance increases with decreasing light intensity?

I set it up how you said, but with a 1000 ohm resistor. I probably made a stupid mistake, not confident at all right now.

[Hutchoo]

Fml. With that ball q.. I wrote "north" instead of up lol. Will I lose a mark for that?

[studynotes]

The output signal was clipped off and inverted? and for the circutary drawing i got 1000 ohms as the resistor since you knew the current from the previous question...