1. CIE Oct/Nov 2018 session papers, marking schemes and other resources have been updated in our papers section.
    Furthermore, we have also updated resources for Edexcel, OCR, IB, TOEFL, SAT, GMAT and more.

    Click here for more information.

    Good luck with your exams.

    Dismiss Notice

Physics: Post your doubts here!

Discussion in 'International A And AS Level' started by XPFMember, Sep 29, 2011.

  1. Hamnah Zahoor

    Hamnah Zahoor

    Messages:
    423
    Likes Received:
    368
    Trophy Points:
    73
    Gender:
    Female
    Location:
    Pakistan
    When the train is at its' maximum speed the acceleration is to be considered zero. Which means the resultant force acting on the train is zero. In order to calculate the force acting:
    P = Fv
    2*10^6 = F (40)
    F = 50,000 N
    Forward force is 50,000 and the resistive force is also 50,000 N which makes the total resultant force equal to zero.
    It is said in the question statement that the resistive force is constant at all speeds thus at 10 ms^-1 Rf= 50,000 N
    P = Fv
    2*10^6 = F(10)
    F = 2*10^5
    Resultant force equals to forward force minus resistive force
    (2*10^5)-(50,000)
    1.5*10^5 N
     
  2. XPC Bot

    Sponsored Listings
  3. Hamnah Zahoor

    Hamnah Zahoor

    Messages:
    423
    Likes Received:
    368
    Trophy Points:
    73
    Gender:
    Female
    Location:
    Pakistan
    No the forward force is used and also in the question I have used F = 400 N not the resultant which is 400-160= 240 N
    Untitled.png
    At the time when acceleration begins the speed is 10 ms^-1 .
     
  4. Raheel327

    Raheel327

    Messages:
    5
    Likes Received:
    2
    Trophy Points:
    3
    How can the acceleration be 0.20ms^-2 when the speed is still 10ms-1?
     
    Hamnah Zahoor likes this.
  5. Ibrahim Yaqoob

    Ibrahim Yaqoob

    Messages:
    1
    Likes Received:
    0
    Trophy Points:
    11
    Gender:
    Male
    I just gave my phy paper2 in oct/nov session . It had a non rectilinear motion question in which we had to calculate max vertical displacement. I made a blunder and took the value of accelaration positive (9.81). It was of three marks i guess. the next question asked KE/GPE. so it subsequently used the height calculated in previous question . I took the other things completely fine.this was of 4 marks. Can anyone guess how much marks will I be losing?
     
  6. Hamnah Zahoor

    Hamnah Zahoor

    Messages:
    423
    Likes Received:
    368
    Trophy Points:
    73
    Gender:
    Female
    Location:
    Pakistan
    Raheel327
    The philosophy of reaching a maximum, any maximum, means that philosophically one is climbing and climbing higher and higher to reach the maximum peak, as long as there is a higher peak one keeps on climbing the slope. Once one reaches the top, the top must be a horizontal plane, even if it is a sharp peak, it must be a plane otherwise one has not reached the maximum.
    Then one goes down the peak.

    So, it is the same with velocity, if the velocity reached is a maximum, one can only go down the slopes around it, after retaining that maximum velocity for some time.
    Untitled.png


    When acceleration is equal to zero than, F =ma a= 0 than resultant force is equal to zero.
     
    Last edited: Nov 5, 2018
  7. Hamnah Zahoor

    Hamnah Zahoor

    Messages:
    423
    Likes Received:
    368
    Trophy Points:
    73
    Gender:
    Female
    Location:
    Pakistan
    As I have shown in the graph above although the acceleration begins to be 0.20 but the initial will remain 10 ms^-1 . the point where it begins it will change after wards.
     
  8. kfemknwnsx

    kfemknwnsx

    Messages:
    6
    Likes Received:
    1
    Trophy Points:
    3
    Gender:
    Male
    has anyone got model diagrams for q1 of p5?
     
  9. Lemniscates

    Lemniscates

    Messages:
    5
    Likes Received:
    2
    Trophy Points:
    3
    Yes.
     
  10. Maheen S

    Maheen S

    Messages:
    1
    Likes Received:
    1
    Trophy Points:
    3
    Could anyone help me with q36 november 2017 variant 11
     
    Hamnah Zahoor likes this.
  11. Hamnah Zahoor

    Hamnah Zahoor

    Messages:
    423
    Likes Received:
    368
    Trophy Points:
    73
    Gender:
    Female
    Location:
    Pakistan
    Untitled.png
     
    Maheen S likes this.
  12. Wâlèé Atèéq

    Wâlèé Atèéq

    Messages:
    316
    Likes Received:
    399
    Trophy Points:
    73
    Gender:
    Male
    Location:
    Karachi
    I missed my lecture of electromagnetism, is there any helpful detailed notes for this topic? Thanks
     
  13. Mr."S"

    Mr."S"

    Messages:
    24
    Likes Received:
    6
    Trophy Points:
    13
    Gender:
    Male
    Is urdu,islamiyat and pak studies required for getting admission at nust
    Because I have e-mailed those guys like 10 times and they don't give a proper answer.Also i have done my olevels from uae and doing a levels in pak
     
  14. Thought blocker

    Thought blocker

    Messages:
    8,513
    Likes Received:
    35,010
    Trophy Points:
    698
    Gender:
    Male
    Location:
    India
  15. kfemknwnsx

    kfemknwnsx

    Messages:
    6
    Likes Received:
    1
    Trophy Points:
    3
    Gender:
    Male
    You will require those 3 subjects. Check the IBCC website though since they're the ones that create the Equivalency Form(you may get some leeway if you are a dual national).
     
  16. Alis alish

    Alis alish

    Messages:
    1
    Likes Received:
    1
    Trophy Points:
    3
    how momentum = impulse?
     
    Hamnah Zahoor likes this.
  17. Hamnah Zahoor

    Hamnah Zahoor

    Messages:
    423
    Likes Received:
    368
    Trophy Points:
    73
    Gender:
    Female
    Location:
    Pakistan
    momentum= mass*velocity
    kg(ms^-1)
    impulse = force*time
    Newton*second
    (kgms^-2) s
    kgms^-1

    units are same thus, both are equal.
     
  18. Navin K

    Navin K

    Messages:
    1
    Likes Received:
    1
    Trophy Points:
    3
    Moemntum is not equal to Impulse

    Change in Momentum = Impulse

    Just like: Transfer of Energy = Work
     
    Hamnah Zahoor likes this.
  19. Clark20

    Clark20

    Messages:
    32
    Likes Received:
    20
    Trophy Points:
    8
    Gender:
    Male
    Need help with this.
     

    Attached Files:

    Hamnah Zahoor likes this.
  20. Hamnah Zahoor

    Hamnah Zahoor

    Messages:
    423
    Likes Received:
    368
    Trophy Points:
    73
    Gender:
    Female
    Location:
    Pakistan
    Mg - T = Ma -------(1)
    T - mg = ma ------(2)

    Make T subject in the second equation
    T = ma + mg
    substitute in first equation
    Mg - (ma+mg) = Ma
    Mg - ma -mg = Ma
    Mg - mg = Ma + ma
    (M - m)g = (M + m)a
    a=(M-m)g/(M+m)
     
  21. Hamnah Zahoor

    Hamnah Zahoor

    Messages:
    423
    Likes Received:
    368
    Trophy Points:
    73
    Gender:
    Female
    Location:
    Pakistan
    Clark20 You know how to make the equations right?
     

Share This Page