Mathematics: Post your doubts here!

[Turki AbdulAziz]

http://maxpapers.com/wp-content/uploads/2012/11/9709_s12_qp_41.pdf
For question 7, why can't I assume that the tensions on both parts of string (BC and BA) are same? I mean the string is not attached to any point between A and C, it is only pulled by a force of 8N. Should i assume that tension is related to length of string between 8N force ??
Pleease Help??

 

[DaniyalK]

http://maxpapers.com/wp-content/uploads/2012/11/9709_s12_qp_41.pdf
For question 7, why can't I assume that the tensions on both parts of string (BC and BA) are same? I mean the string is not attached to any point between A and C, it is only pulled by a force of 8N. Should i assume that tension is related to length of string between 8N force ??
Pleease Help??

The 2 parts of the string are at different angles.

 

[hizirofaki]

Q1 why did we take negaive 0.32 and 0.28 it should be only 0.32 right?

 

[farhan141]

Q1 why did we take negaive 0.32 and 0.28 it should be only 0.32 right?

What do u mean?

Here:

 

[hizirofaki]

What do u mean?

Here:View attachment 53487

thx
but in the ii part how did u now that v =0

 

[farhan141]

thx
but in the ii part how did u now that v =0

They said how far it can go so that means final velocity will be 0. And it has negative acceleration so that also tells u that it is slowing down

 

[DESTROYER1198]

can some one help please.. im really confused on when to take the weight component of an object into consideration because sometimes i use it where im nt supposed to and sometimes i dont use where im supposed to use it. For example I didnt know that we need to use it in s14 p43 Q2 (what i mean by the weight component is the gravity force exerted on the mass of the object at an inclined plane which is usually calculated by mgSin(Theta) )

 

[Math Buddy]

Q3 explanation please?

 

[DeadlYxDemon]

can some one help please.. im really confused on when to take the weight component of an object into consideration because sometimes i use it where im nt supposed to and sometimes i dont use where im supposed to use it. For example I didnt know that we need to use it in s14 p43 Q2 (what i mean by the weight component is the gravity force exerted on the mass of the object at an inclined plane which is usually calculated by mgSin(Theta) )

 

[DaniyalK]

can some one help please.. im really confused on when to take the weight component of an object into consideration because sometimes i use it where im nt supposed to and sometimes i dont use where im supposed to use it. For example I didnt know that we need to use it in s14 p43 Q2 (what i mean by the weight component is the gravity force exerted on the mass of the object at an inclined plane which is usually calculated by mgSin(Theta) )

Always use it when you are using newton's second law ( Fnet = ma)

View attachment 53489 Q3 explanation please?

i)V = P/F
If P increases, V increases, so Vb = 1.2* 28
If F decreases then V increases, so Vb = (1.2 * 28)/0.96 (multiplying by 0.96 will decrease V, so it's divided)

ii)Work done by Driving force + Loss = Work done by resistive force + gain
WD + 0 = (2.3 * 10^6) + (.5)(200000)(35^2-28^2)

 

[Math Buddy]

Always use it when you are using newton's second law ( Fnet = ma)


i)V = P/F
If P increases, V increases, so Vb = 1.2* 28
If F decreases then V increases, so Vb = (1.2 * 28)/0.96 (multiplying by 0.96 will decrease V, so it's divided)

ii)Work done by Driving force + Loss = Work done by resistive force + gain
WD + 0 = (2.3 * 10^6) + (.5)(200000)(35^2-28^2)

thank you bhai

can some one help please.. im really confused on when to take the weight component of an object into consideration because sometimes i use it where im nt supposed to and sometimes i dont use where im supposed to use it. For example I didnt know that we need to use it in s14 p43 Q2 (what i mean by the weight component is the gravity force exerted on the mass of the object at an inclined plane which is usually calculated by mgSin(Theta) )

 

[hizirofaki]

graph plz

 

[qwertypoiu]

graph plz

 

[farhan141]

graph plz

 

[Serial_Ripper]

P4 MJ 06 Q5 (i) .... I SERIOUSLY DON'T GET IT! -freaking out-

 

[Math Buddy]

q6 explain

 

[DaniyalK]

P4 MJ 06 Q5 (i) .... I SERIOUSLY DON'T GET IT! -freaking out-

Tension on both sides of the pulley is same, so the right angle can be split into 2 45 degree angles. If you resolve one of these, it's Tcos45.
Since there are 2 of these, the resultant is equal to 2Tcos45
2Tcos45 =4sqrt2

 

[Laibaaa]

How do we calculate V for the first part?
Ive uploaded mark scheme as well

i saw the mark scheme but it was pretty confusing can anyone please tell me how to form an equation as well?

 

[DaniyalK]

How do we calculate V for the first part?
Ive uploaded mark scheme as well

i saw the mark scheme but it was pretty confusing can anyone please tell me how to form an equation as well?

Driving force = P/V
P/V - Fr = ma
30000/Vinitial - 12500(30/500) - 1000 = 1250(4)
and
30000/Vfinal -12500(30/500) - 1000 = 1250(0.2)

 

[Laibaaa]

Driving force = P/V
P/V - Fr = ma
30000/Vinitial - 12500(30/500) - 1000 = 1250(4)
and
30000/Vfinal -12500(30/500) - 1000 = 1250(0.2)

Whats - 12500 (30/500) ?