WJEC S3 22nd June 2015

Original post by L'Evil Fish

Yeah should be fine!

Last question was very nice.

Impulse was newer

But yes, that SHM proof, I thought I'd forgotten something major, but I got it all out in the end.

The M3 impulse question was almost identical to a past paper question, the only difference being part a). I was quite surprised actually, because initially I thought that it would be complicated but it literally had the exact same answers as a past paper I'd done the night before haha.
I thought the SHM question was the new one, as I don't think they've given two springs before.

Reply 23

Original post by Luke1324

The M3 impulse question was almost identical to a past paper question, the only difference being part a). I was quite surprised actually, because initially I thought that it would be complicated but it literally had the exact same answers as a past paper I'd done the night before haha.
I thought the SHM question was the new one, as I don't think they've given two springs before.

4 and 4 root3? :tongue:

for components

Yeah, it was a nice question tbf, kudos to them. Was very nice how it worked at all points

Reply 24

Original post by L'Evil Fish

4 and 4 root3? :tongue:

for components

Yeah, it was a nice question tbf, kudos to them. Was very nice how it worked at all points

4's do ring a bell! I thought the differential equation question was nice, and a friend informed me that it was actually the equation for underdamped simple harmonic motion, which explains why the displacement was zero :smile:

Reply 25

Original post by Luke1324

4's do ring a bell! I thought the differential equation question was nice, and a friend informed me that it was actually the equation for underdamped simple harmonic motion, which explains why the displacement was zero :smile:

Yep! That's what it was, I thought it would have been nice if they asked what I signified but I don't think it's on the syllabus

Reply 26

Original post by L'Evil Fish

Yep! That's what it was, I thought it would have been nice if they asked what I signified but I don't think it's on the syllabus

I think the hardest question on there was definitely the SHM questions. It took me quite a while to show the equilibrium position and that it was SHM, but I got there in the end.

Reply 27

Original post by Luke1324

I think the hardest question on there was definitely the SHM questions. It took me quite a while to show the equilibrium position and that it was SHM, but I got there in the end.

It's annoying that the places I'll probably lose marks are the simple variable kinematics with slips.

Not even the hard stuff, at one point I was thinking about energy considerations to find max speed to find amplitude :rofl:

But then it said 'write down' meaning no calculations necessary

Good thing they gave the period or I wouldn't have gotten an answer out

Reply 28

Original post by L'Evil Fish

It's annoying that the places I'll probably lose marks are the simple variable kinematics with slips.

Not even the hard stuff, at one point I was thinking about energy considerations to find max speed to find amplitude :rofl:

But then it said 'write down' meaning no calculations necessary

Good thing they gave the period or I wouldn't have gotten an answer out

Yeah the period helped, I ended up showing that the acceleration was proportional to the displacement and the constant was 100/9, which was w^2, then used that to find the period. I think I'll lose marks on the impulsive tension part a) as I only drew a picture, which I don't think is a mathematical method :colondollar:

Sine rule is probably what they want

Reply 29

Original post by Luke1324

Yeah the period helped, I ended up showing that the acceleration was proportional to the displacement and the constant was 100/9, which was w^2, then used that to find the period. I think I'll lose marks on the impulsive tension part a) as I only drew a picture, which I don't think is a mathematical method :colondollar:

Sine rule is probably what they want

I did that for 3 places to show it was true, but then crossed it out and did a general case using extension of each spring. And it worked out

Might get a mark

Yeah I used sin rule, and sum to 180 for triangle

Reply 30