Physics: Post your doubts here!

[usama321]

View attachment 35948
why is answer A

While checking for an elastic collision, we see whether the statement "relative speed of approach was equal to relative speed of separation" is satisfied
Now the key term is 'relative'. For two bodies moving in opposite direction to each other, let's say, you are driving at 50 km/h, and there is another car coming towards you at 50 km/h. Thus, the relative speed of the incoming car would be 100km/h, as you are going in the opposite direction.

Now let's say you are overtaking a car which is driving at around 50 km/h, while you are driving at 60 km/h. Your relative speed would thus be 10 km/h only.

Now, let's look at the question. (NOTE: The question is talking about speed, not velocity)

Ux and Uy are moving in opposite directions, thus their speeds are added as we are finding about the relative speed.
Vx and Vy are moving in opposite directions, thus again their speeds are added.

 

[Asad rehman]

Stationary wave is produced inside the tube ...it means it has nodes and antinodes...and max displacement is at antinodes and min at nodes so dust heaps are formed on nodes (as the displacement at nodes is zero).

but whare heaps are formed when water is drained off.

 

[farahroslend]

Salam.

Can anyone help me with this A2 Paper 4 Physics question on electromagnetism and nuclear physics?

Please provide with as much explanation as possible...

Thank you.

May Allah repay your kindness.

Amin.


Electromagnetism:

Question 6. (c)

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_s09_qp_4.pdf


Nuclear Physics:

Question 9 (b)

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_s09_qp_4.pdf


http://papers.xtremepapers.com/CIE/...and AS Level/Physics (9702)/9702_s09_qp_4.pdf

 

[ashcull14]

Help plx wid full a-z explanation

 

[ZaqZainab]

Help plx wid full a-z explanation

the answer would be B write the units of what they have given us
so we know distance is L and time is T so L is meter and time is second and a is radius which is in meters
the equation L(3+(a^2/P)=QT^2 sin teta
3,and sin teta are constants we can remove them

using units -> m(m^2/P)=Q*s^2

we have to have LHS=RHS
there is no seconds on the left hand side so we have to remove seconds we will know that one of the value of Q is s^-2 that's the only way to remove Q(xs^-2) we don't know x yet
we will have
m(m^2/p)=xs^-2*s^2 => m(m^2/p)=x As its only x and not squared or raised to anything m=x and as there is only m on the left hand side
we have to still find p we know x=m so m(m^2/p)=m
p=m^2
and so q=ms^-2

 

[ashcull14]

THNK u so much ....tht ws vry hlpful..

 

[ashcull14]

can u kindly answer the 2nd question also?..

 

[ZaqZainab]

can u kindly answer the 2nd question also?..

Well i having trouble in that is the answer B?

 

[TheStallion-Reborn]

Can someone please help me with the concept of deriving physical equations??

 

[usama321]

Help plx wid full a-z explanation

Calculate the percentage uncertainties for all the values. The one with the largest percentage uncertainty should cause the highest uncertainty in the answer
A: .002/2.043 * 100
B: (2*0.02)/.52 *100 (multiply the uncertainty with 2 due to the exponent)
C: .01/19.62 * 100
D: 0.2/5.2 * 100

The answer should be B as it has the highest percentage uncertainty.

Can someone please help me with the concept of deriving physical equations??

Do you have physics pacific book? You will find a good explanation there... If you don't, i'll try explaining it here.

 

[TheStallion-Reborn]

Do you have physics pacific book? You will find a good explanation there... If you don't, i'll try explaining it here.

Yes I do. Can you please refer me to the page number?

 

[usama321]

Yes I do. Can you please refer me to the page number?

Page 9

 

[usama321]

Check out the examples too

 

[TheStallion-Reborn]

can someone please explain how to calculate phase differnce? #waves

 

[Hassan Ali Abid]

can someone please explain how to calculate phase differnce? #waves

Phase difference = (x/lamda).360 or (x/lamda).2pie , where lamda = wave length and x = the horizontal displacement of the point from where new wave will be drawn.

 

[TheStallion-Reborn]

Phase difference = (x/lamda).360 or (x/lamda).2pie , where lamda = wave length and x = the horizontal displacement of the point from where new wave will be drawn.

you mean that if i have to find the phase difference of 2 points within wave, X will be the horizontal distance between those 2 points?

 

[Hassan Ali Abid]

you mean that if i have to find the phase difference of 2 points within wave, X will be the horizontal distance between those 2 points?

Yes ...

 

[Hassan Ali Abid]

TheStallion-Reborn see it ..i hope u will understand it

 

[TheStallion-Reborn]

TheStallion-Reborn see it ..i hope u will understand it

Thankyouu!!!

 

[goodluckayesha]

i have a few doubts plz someone kindly explain (A2 questions)
http://papers.xtremepapers.com/CIE/...and AS Level/Physics (9702)/9702_s09_qp_4.pdf Q10 part cii mark scheme says 9v how does the answer come?
http://papers.xtremepapers.com/CIE/...nd AS Level/Physics (9702)/9702_s10_qp_42.pdf Q10b
http://papers.xtremepapers.com/CIE/...nd AS Level/Physics (9702)/9702_s11_qp_41.pdf Q9biii the V- decreases as temp is increasing but y is vout -9 or +9 y not taking +5v into account as in part Q9bii?