Edexcel AS/A2 Mathematics M1 - 8th June 2016 - Official Thread

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how did you solve 7(b)?

tension acts away from the pulley so resolve the forces of tension then add them together

the resultant force of the tension acting upon the pulley is equal to the weight of the particle on the rod i think

(edited 7 years ago)

Reply 381

Cryptokyo

Original post by Elaria

how did you solve 7(b)?

You know that the tension in the string is 12.6N from part a and this is used to find the force exerted on the pulley.
Diagram 2.png

The force exerted on the pulley is the vector sum of the tensions acting upon it hence the force exerted on the pulley is

2T\cos(90-\alpha)=2T\sin(\alpha)

. So the force exerted on the pulley is

2\times12.6\times\frac{3}{4}=18.6

(edited 7 years ago)

Reply 382

Cryptokyo

@Marxist @RKM21 @KloppOClock

A pulley question.
Pulley Q.png

Answer in spoiler

[edit: answer now correct]

Spoiler

(edited 7 years ago)

Reply 383

fpmaniac

Can anyone explain to me how the forces on the blocks in scale pans work in general. E.g.
|Block A|
| BlockB |
What will be the forces acting on Block A an B assuming Block A is above block B and block B is on the scale Pan

Reply 384

83457

Original post by kkboyk

Recent AQA papers, and also Delphis ones.

Can I theoretically do them with Edexcel m1 and m2 knowledge? And do they have 3d vectors like with OCR MEI?

Reply 385

Cryptokyo

Original post by 83457

Can I theoretically do them with Edexcel m1 and m2 knowledge? And do they have 3d vectors like with OCR MEI?

Delphis has certain papers for Edexcel. AQA is less in the style of an Edexcel paper but still useful. You should be able to do nearly all the questions in the AQA papers and all questions in the Delphis for Edexcel papers.

Reply 386

fpmaniac

Someone explain to me how the forces work here pls. I dont understand how the horizontal force works.
http://postimg.org/image/phad5dk3f/bb77638f/

Reply 387

Kevin De Bruyne

Original post by fpmaniac

Someone explain to me how the forces work here pls. I dont understand how the horizontal force works.
http://postimg.org/image/phad5dk3f/bb77638f/

Think of the 30N force as being a z angle, so the angle between the line representing 30N and the force is alpha as well.

Reply 388

Cryptokyo

Original post by KINGYusuf

I'm sorry if I'm being annoying, I just don't get this part of vectors :frown:

Isn't BQ the same as OP, but in the opposite direction?

No it is not. They have different directions and are therefore different vectors.

Posted from TSR Mobile

Reply 389

fpmaniac

Original post by SeanFM

Think of the 30N force as being a z angle, so the angle between the line representing 30N and the force is alpha as well.

Thanx. Can you or anyone else. also help me with a few more queries I have. What direction does thrust act in. I thought it was in direction of motion but they did something different on question 1c on M1 specimen paper.
Also what do you do for questions where theres a pulley and then it says the string breaks. Do you not consider the tension anymore? There was a question which said the string broke then immediately the particle stopped You had to find out the time between when the string broke and the particle stopped. However they took the forward force as 0 but even if the particle moved slightly wouldnt there be a forward force? (Jan 2011 question 7c)

Reply 390

nicoledsk

i'd really appreciate some help with part (c) i'm a bit confused on what happens to direction of thrust when the forward force is removed. is it equal and opposite because i tried that and got a different answer to the markscheme?

Spoiler

Reply 391

philo-jitsu

Whilst looking over the edge of a vertical cliff, 122.5 metres in height, Jim dislodges a stone.The stone falls freely from rest towards the sea below.Ignoring the effect of air resistance,

(a) calculate the time it would take for the stone to reach the sea, (3 marks)

(b) find the speed with which the stone would hit the water. (2 marks)Two seconds after the stone begins to fall, Jim throws a tennis ball downwards at the stone.The tennis ball’s initial speed is u ms-1 and it hits the stone before they both reach the water.

(c) Find the minimum value of u. (5 marks)

(d) If you had taken air resistance into account in your calculations, what effect would thishave had on your answer to part (c)? Explain your answer. (2 marks)

Can anyone help with part C, no matter what I did I had 2 variables and one equation, then the answer got rid of a variable by using the original 'S' as distance in the S=ut+(at^2)/2.

I get that they did T-2 as it was thrown 2 seconds after, but id the balls collided before hitting the water how can they still use the original distance when 'S' has to be less as they collide before reaching the water? Madness!?

Reply 392

KloppOClock

Original post by nicoledsk

Spoiler

[Trailer] <--------> [Car]

the arrow is the direction of thrust
also it says the magnitude of thrust is 100N

if you dont get that I can draw a diagram for you

(edited 7 years ago)

Reply 393

KloppOClock

Original post by Cryptokyo

@Marxist @RKM21 @KloppOClock

A pulley question.
Pulley Q.png

Answer in spoiler

[edit: answer now correct]

Spoiler

would there be tension when A and B are back to there original position, or if A and B reach a height of 2L? Also if A gets tension before B does after reaching its original position first, does it rebound?

Reply 394

99joey

When doing velocity vector questions, do we have to underline the vector components such as i and j constantly and would we lose marks if we didn't?

Reply 395

philo-jitsu

Original post by 99joey

When doing velocity vector questions, do we have to underline the vector components such as i and j constantly and would we lose marks if we didn't?

no, just use the bracket method, they dont penalise you for using this method

Reply 396

99joey

Original post by philo-jitsu

no, just use the bracket method, they dont penalise you for using this method

oh ok, however if they asked us present it in the format i and j, would I then be penalised if I didn't underline the vectors?

Reply 397

nicoledsk

Original post by KloppOClock

[Trailer] <--------> [Car]

the arrow is the direction of thrust
also it says the magnitude of thrust is 100N

if you dont get that I can draw a diagram for you

thanks very much! i finally got the right answer!

Reply 398

philo-jitsu

Original post by 99joey

oh ok, however if they asked us present it in the format i and j, would I then be penalised if I didn't underline the vectors?

As far as Im aware they cant penalise you...but to be safe you can figure it out in bracket method then just stick the answer down in the format they asked for, but usually in a mark scheme it says accept bracket method (or alternative)