# Edexcel M4 Exam Discussion Thread [June 5th] Watch

Announcements

Report

#202

(Original post by

So can i Assume that 68/75 will be an 90UMS ?

**HashiramaSenju**)So can i Assume that 68/75 will be an 90UMS ?

Anyway all that is not to be bragging about my class but to say that I imagine, looking at previous grade boundaries, that the a* will be one or two marks lower than normal, possibly. I think people who don't really like M4 or don't love mechanics will struggle a bit with the paper, or at least freak out enough to mess something up e.g. seeing that stability question confused quite a few people in my class for long enough that it ate into their time before they could figure out what to do.

0

reply

Report

#203

(Original post by

I got π/3. If someone posts the paper I can do model answers

**Gome44**)I got π/3. If someone posts the paper I can do model answers

0

reply

Report

#204

(Original post by

I heard your parents took you to a freak show and got invited on stage

**UKMT owner**)I heard your parents took you to a freak show and got invited on stage

0

reply

Report

#205

These are my quick attempts based of a sketchy memory of the paper and what I wrote. Be sure to tell me if I've made a mistake.

Edit:cos(2t) should be -0.5 and t=pi/3.

0

reply

Report

#206

(Original post by

Funnily enough when I saw your mum the other night she said the same thing, not about the post of course but something else

She was also quite thick

I can see the genes being passed on

But don't worry half of your brother in 9 months time's genes would be much better

**UKMT owner**)Funnily enough when I saw your mum the other night she said the same thing, not about the post of course but something else

She was also quite thick

I can see the genes being passed on

But don't worry half of your brother in 9 months time's genes would be much better

0

reply

Report

#207

(Original post by

How do you know it'll be a boy?

**Gome44**)How do you know it'll be a boy?

**UKMT owner**)

Funnily enough when I saw your mum the other night she said the same thing, not about the post of course but something else

She was also quite thick

I can see the genes being passed on

But don't worry half of your brother in 9 months time's genes would be much better

can you two please get a ****ing room and stop poisoning the whole thread? nobody else cares about this

1

reply

Report

#208

(Original post by

These are my quick attempts based of a sketchy memory of the paper and what I wrote. Be sure to tell me if I've made a mistake.

Edit:cos(2t) should be -0.5 and t=pi/3.

**Gawain**)These are my quick attempts based of a sketchy memory of the paper and what I wrote. Be sure to tell me if I've made a mistake.

Edit:cos(2t) should be -0.5 and t=pi/3.

1

reply

Report

#209

(Original post by

I think you copied the second order DE down wrong, it should be x=....+sin(2t)*(1/6), resulting in D=-1/12

**Gome44**)I think you copied the second order DE down wrong, it should be x=....+sin(2t)*(1/6), resulting in D=-1/12

I think I got the direction wrong for Q2.

If the question asked for the direction 'from' ( I probably misread the question) then it's a bearing of 180+76=256.

0

reply

Report

#210

(Original post by

Yeah a negative D sounds right. I don't have a copy of the paper with me so I wouldn't be surprised if I made mistakes copying stuff down.

I think I got the direction wrong for Q2.

If the question asked for the direction 'from' ( I probably misread the question) then it's a bearing of 180+76=256.

**Gawain**)Yeah a negative D sounds right. I don't have a copy of the paper with me so I wouldn't be surprised if I made mistakes copying stuff down.

I think I got the direction wrong for Q2.

If the question asked for the direction 'from' ( I probably misread the question) then it's a bearing of 180+76=256.

0

reply

Report

#212

Just got back. Wasn't a bad paper for M4. Would a mark of 60-65 be 80-85 UMS?

I believe I got most of the paper correct, but there were two questions I messed up. Cut my losses with the second relative motion question, as the diagram wasn't working for me. Annoyingly I completely ****ed up the 2nd order ODE question, so lost quite a few marks there.

I believe I got most of the paper correct, but there were two questions I messed up. Cut my losses with the second relative motion question, as the diagram wasn't working for me. Annoyingly I completely ****ed up the 2nd order ODE question, so lost quite a few marks there.

0

reply

Report

#213

Don't worry, 1) the grade boundaries won't be high although it was an easy paper, there are still a lot people not doing well.

2) comparing to this, the easier M5(i mean on the maths part) might be hard, so it's time to revise

2) comparing to this, the easier M5(i mean on the maths part) might be hard, so it's time to revise

__M5 thread: http://www.thestudentroom.co.uk/show...6054625%202015__
0

reply

Report

#215

I look to have got most of it right but I am not sure about the bearing shouldn't it be 90-arctan(4/16) people on here are saying its 180 degrees since it asked where the wind acts from but wasn't your Vw=16i+4j the velocity the wind is acting from anyway so you shouldn't have had to add 180 it was acting from North and then from (16i+12j I think) so its got to act from around those angles I am not really sure about this though as direction and magnitudes are very confusing when it comes to relative motion.

The stability question they asked was very hard but I had seen it on a past paper a few days ago so I just copied down the same method with different numbers and even then that took me a while in the exam and there is no way I would have got that right in time if I hadn't done it before as it took me ages the first time.People on here seem to have used a better method than mine I did cosine rule and pythagoras with a circle theorem(angle in semicircle 90 degrees) to get the distances I needed).

The second order differential equation was a bit unusual and I hadn't seen it before I did it by splitting up the string into two strings and consider the extensions in both, for the last part using the adding trig to multiple of trig formulas was the easiest way I think and then simply solving both and selecting the shortest time.The coefficient of restitution(last question) was a bit sneaky in that you need w in terms of u and to do that you had to mess on with the addition formulas for 60-beta so that your answers were exact.

Overall I think it was an average/maybe slightly hard paper it was certainly harder than the paper which was 65 for an A(that paper was really easy you had to simply do basic conservation of momentum no M4 needed and sub relative velocities into formulas and solve a basic SHM problem) I think probably high 50s for an A around 58-60(with A* probably around 65-67) as the boundaries for M4 are usually pretty low.I

The stability question they asked was very hard but I had seen it on a past paper a few days ago so I just copied down the same method with different numbers and even then that took me a while in the exam and there is no way I would have got that right in time if I hadn't done it before as it took me ages the first time.People on here seem to have used a better method than mine I did cosine rule and pythagoras with a circle theorem(angle in semicircle 90 degrees) to get the distances I needed).

The second order differential equation was a bit unusual and I hadn't seen it before I did it by splitting up the string into two strings and consider the extensions in both, for the last part using the adding trig to multiple of trig formulas was the easiest way I think and then simply solving both and selecting the shortest time.The coefficient of restitution(last question) was a bit sneaky in that you need w in terms of u and to do that you had to mess on with the addition formulas for 60-beta so that your answers were exact.

Overall I think it was an average/maybe slightly hard paper it was certainly harder than the paper which was 65 for an A(that paper was really easy you had to simply do basic conservation of momentum no M4 needed and sub relative velocities into formulas and solve a basic SHM problem) I think probably high 50s for an A around 58-60(with A* probably around 65-67) as the boundaries for M4 are usually pretty low.I

0

reply

Report

#216

(Original post by

I look to have got most of it right but I am not sure about the bearing shouldn't it be 90-arctan(4/16) people on here are saying its 180 degrees since it asked where the wind acts from but wasn't your Vw=16i+4j the velocity the wind is acting from anyway so you shouldn't have had to add 180 it was acting from North and then from (16i+12j I think) so its got to act from around those angles I am not really sure about this though as direction and magnitudes are very confusing when it comes to relative motion.

The stability question they asked was very hard but I had seen it on a past paper a few days ago so I just copied down the same method with different numbers and even then that took me a while in the exam and there is no way I would have got that right in time if I hadn't done it before as it took me ages the first time.People on here seem to have used a better method than mine I did cosine rule and pythagoras with a circle theorem(angle in semicircle 90 degrees) to get the distances I needed).

The second order differential equation was a bit unusual and I hadn't seen it before I did it by splitting up the string into two strings and consider the extensions in both, for the last part using the adding trig to multiple of trig formulas was the easiest way I think and then simply solving both and selecting the shortest time.The coefficient of restitution(last question) was a bit sneaky in that you need w in terms of u and to do that you had to mess on with the addition formulas for 60-beta so that your answers were exact.

Overall I think it was an average/maybe slightly hard paper it was certainly harder than the paper which was 65 for an A(that paper was really easy you had to simply do basic conservation of momentum no M4 needed and sub relative velocities into formulas and solve a basic SHM problem) I think probably high 50s for an A around 58-60(with A* probably around 65-67) as the boundaries for M4 are usually pretty low.I

**Dalek1099**)I look to have got most of it right but I am not sure about the bearing shouldn't it be 90-arctan(4/16) people on here are saying its 180 degrees since it asked where the wind acts from but wasn't your Vw=16i+4j the velocity the wind is acting from anyway so you shouldn't have had to add 180 it was acting from North and then from (16i+12j I think) so its got to act from around those angles I am not really sure about this though as direction and magnitudes are very confusing when it comes to relative motion.

The stability question they asked was very hard but I had seen it on a past paper a few days ago so I just copied down the same method with different numbers and even then that took me a while in the exam and there is no way I would have got that right in time if I hadn't done it before as it took me ages the first time.People on here seem to have used a better method than mine I did cosine rule and pythagoras with a circle theorem(angle in semicircle 90 degrees) to get the distances I needed).

The second order differential equation was a bit unusual and I hadn't seen it before I did it by splitting up the string into two strings and consider the extensions in both, for the last part using the adding trig to multiple of trig formulas was the easiest way I think and then simply solving both and selecting the shortest time.The coefficient of restitution(last question) was a bit sneaky in that you need w in terms of u and to do that you had to mess on with the addition formulas for 60-beta so that your answers were exact.

Overall I think it was an average/maybe slightly hard paper it was certainly harder than the paper which was 65 for an A(that paper was really easy you had to simply do basic conservation of momentum no M4 needed and sub relative velocities into formulas and solve a basic SHM problem) I think probably high 50s for an A around 58-60(with A* probably around 65-67) as the boundaries for M4 are usually pretty low.I

0

reply

Report

#218

what was everyone getting if you wrote the direction if the wind as a bearing?

Posted from TSR Mobile

Posted from TSR Mobile

0

reply

Report

#219

(Original post by

what was everyone getting if you wrote the direction if the wind as a bearing?

Posted from TSR Mobile

**CowsWhoStare**)what was everyone getting if you wrote the direction if the wind as a bearing?

Posted from TSR Mobile

0

reply

Report

#220

[QUOTE=CowsWhoStare;56631397]what was everyone getting if you wrote the direction if the wind as a bearing?

I got 284. 360 - arctan (16/4).

Posted from TSR Mobile

I got 284. 360 - arctan (16/4).

Posted from TSR Mobile

0

reply

X

### Quick Reply

Back

to top

to top