Author Topic: All Mechanics DOUBTS HERE!!! (Read 88428 times)

RoRo · « **Reply #405 on:** March 21, 2011, 11:57:36 am »

Quote from: astarmathsandphysics on March 20, 2011, 11:42:00 pm

look at the arrows on the 8N force on the diagram below. The force is pushing the block into the plane

Oh, okay, I got it, thanks a lot!

The Golden Girl =D · « **Reply #406 on:** March 22, 2011, 04:03:54 pm »

Chapter 6 , Page 146 , Q1}a] ..... Q2}a] ....and Q4}a]

I NEED this URGENTLY

elemis · « **Reply #407 on:** March 22, 2011, 04:05:54 pm »

Quote from: ~ The Golden Girl ~ on March 22, 2011, 04:03:54 pm

Chapter 6 , Page 146 , Q1}a] ..... Q2}a] ....and Q4}a]

I NEED this URGENTLY

10 minutes.

elemis · « **Reply #408 on:** March 22, 2011, 04:10:45 pm »

Position vector after a time = Initial Position vector + velocity*time

Hence,
Q1
r = 3j +8i
= 8i +3j

Q2
6i+13j = 2i+3j + 2v

4i +10j = 2v

2i +5j= v

Can you apply the same method for Question 4 ?

The Golden Girl =D · « **Reply #409 on:** March 22, 2011, 04:14:21 pm »

Quote from: Ari Ben Canaan on March 22, 2011, 04:10:45 pm

Position vector after a time = Initial Position vector + velocity*time

Hence,
Q1
r = 3j +8i
= 8i +3j

Q2
6i+13j = 2i+3j + 2v

4i +10j = 2v

2i +5j= v

Can you apply the same method for Question 4 ?

Thanks mate

RoRo · « **Reply #410 on:** April 07, 2011, 07:25:36 pm »

I've got a long list of doubts this time!

Check the attachment for the questions and the answers [at the bottom]

I need the steps for the following questions:

4b)
5a)b)
7c)d)
8c)

Thanks A LOT in advance!

iluvme · « **Reply #411 on:** April 07, 2011, 08:15:56 pm »

4 b)

Not sure about the others :S

RoRo · « **Reply #412 on:** April 07, 2011, 08:32:56 pm »

Quote from: i<3SL on April 07, 2011, 08:15:56 pm

4 b)

Not sure about the others :S

Thank you so much!

I did a super-stupid mistake, instead of adding 4 to 3 and writing the answer as 7, I wrote it as 1! -.-"

Darkstar3000 · « **Reply #413 on:** April 09, 2011, 03:53:29 pm »

Question 5 Jan 2008 : http://www.carlgauss.co.uk/PDFs/A-Level%20Papers/M2/M2%20-%202008%20Jan%20Paper.pdf

Mark scheme : http://www.carlgauss.co.uk/PDFs/A-Level%20Papers/M2/M2%20-%202008%20Jan%20Mark%20Scheme.pdf

Am I wrong or is the mark scheme wrong because when I calculate the answer I'm getting 0.72 but they get 0.18

----------------------------------------------------------

How do I do question number 6, the whole thing ?

Thanks

elemis · « **Reply #414 on:** April 09, 2011, 07:10:41 pm »

I will answer this tomorrow morning.

elemis · « **Reply #415 on:** April 10, 2011, 06:20:02 am »

Question 5

Considering vertical forces you will find that R = 4mg

Taking moments about point B :

2a*cos60*mg + 3a*cos60*3mg + 4a*cos30*4mg $\mu$ = 4a*cos60*4mg

Solve this and you will get an answer of : 0.180

Question 6

Attempt the question and show me your workings. I'll see where you've gone wrong and correct you.

Darkstar3000 · « **Reply #416 on:** April 10, 2011, 11:59:08 am »

Quote from: Ari Ben Canaan on April 10, 2011, 06:20:02 am

Question 5

Considering vertical forces you will find that R = 4mg

Taking moments about point B :

2a*cos60*mg + 3a*cos60*3mg + 4a*cos30*4mg $\mu$ = 4a*cos60*4mg

Solve this and you will get an answer of : 0.180

Question 6

Attempt the question and show me your workings. I'll see where you've gone wrong and correct you.

Thank you for question 5.

As for 6, I have no idea where to start it

jellybeans · « **Reply #417 on:** April 11, 2011, 08:01:44 am »

Question on the motion of a projectile on an inclined plane

For (a) I equated j component = 0
-> (UsinthetaT - ½gcosthetaT²) = 0
-> (Usin60T - ½gcos30T²) = 0
-> T=0, (root3)U/2 - (root3)g/4(T))T=0
-> (root3)g/4(T) = (root3)U/2
so i got -> T=2U/g

but it says 2U/g(root3)

could somebody help me on this question please.. thanks!

RoRo · « **Reply #418 on:** April 12, 2011, 12:40:02 pm »

Can anyone please solve for me Question 1 in January 2006 and Question 8d in June 2005 [Edexcel Papers] with explanation?

Thank you!

HUSH1994 · « **Reply #419 on:** April 17, 2011, 12:55:21 pm »

MJ 2003 Q4 part 2,i did it wrong and then the mark scheme had 2 dots above x,anyone can help me with this

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