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Physics: Post your doubts here!

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Can anyone just explain me how to get amplitude?
20% K.E is lost so left is 80% that means 12 but I can't understand anything further than that.
 
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http://studyguide.pk/Past Papers/CIE/International A And AS Level/9702 - Physics/9702_w08_qp_2.pdf
Question 6 part bi, the ER says that describe what will be seen as a result of diffraction of water waves. What do I write in that?
And bii? question 7 a?and bii? And 8 c as well! Anyone PLEASE! :(
6) b) i) Just outline the ripple tank experiment. You can either draw the ripple tank or describe it. For the diffraction of the water waves, just simply state that you put 2 wooden blocks in the ripple tank with a small gap between them to create diffracted waves. Also state the method to detect the waves such as a lamp to see the water waves clearly and a viewing screen below the tank or a stroboscope to freeze the waterfronts.
b) ii) For sound, just say that you put 2 identical speakers which are connected to the same power supply and a slit to create the diffraction pattern. Normally for sound when diffraction occurs, you can hear loud sounds and then soft or no sound at all. Place a microphone which is connected to a cro and move it along the length of the slit. If its destructive interference/ no sound, then the cro will show zero ampltude.
7) a) E=I(P+Q)
I=V/R (This is in terms of p because question wants voltage across P)
I=V/P Sub into E
E= V/P(P+Q)
V= EP/P+Q
b) ii) Let the parallel resistance be R
Use the equation V= (P/P+Q)E
3.6 = (2000/2000+R)6.0
R=1333.333 ohm
1/1333.33= 1/5000+ 1/ Rth
Rth=1820 ohm
8) c) Spontaneous process means the decay process is not affected by external factors such as temperature.
Hence, both the curves have a similar shape.
 
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6) b) i) Just outline the ripple tank experiment. You can either draw the ripple tank or describe it. For the diffraction of the water waves, just simply state that you put 2 wooden blocks in the ripple tank with a small gap between them to create diffracted waves. Also state the method to detect the waves such as a lamp to see the water waves clearly and a viewing screen below the tank or a stroboscope to freeze the waterfronts.
b) ii) For sound, just say that you put 2 identical speakers which are connected to the same power supply and a slit to create the diffraction pattern. Normally for sound when diffraction occurs, you can hear loud sounds and then soft or no sound at all. Place a microphone which is connected to a cro and move it along the length of the slit. If its destructive interference/ no sound, then the cro will show zero ampltude.
7) a) E=I(P+Q)
I=V/R (This is in terms of p because question wants voltage across P)
I=V/P Sub into E
E= V/P(P+Q)
V= EP/P+Q
b) ii) Let the parallel resistance be R
Use the equation V= (P/P+Q)E
3.6 = (2000/2000+R)6.0
R=1333.333 ohm
1/1333.33= 1/5000+ 1/ Rth
Rth=1820 ohm
8) c) Spontaneous process means the decay process is not affected by external factors such as temperature.
Hence, both the curves have a similar shape.
Sorry to bother you time and again, but could you check question 2, in ai, It's mentioned that the speed before the brakes are applied so shouldn't we use the distance 29.3? Whereas in the MS 12.8 is used? 12.8 is the distance after the brakes are applied, no? And for the same question ii, we're using s=vt. How do we know that the velocity is constant?
 
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6) b) i) Just outline the ripple tank experiment. You can either draw the ripple tank or describe it. For the diffraction of the water waves, just simply state that you put 2 wooden blocks in the ripple tank with a small gap between them to create diffracted waves. Also state the method to detect the waves such as a lamp to see the water waves clearly and a viewing screen below the tank or a stroboscope to freeze the waterfronts.
b) ii) For sound, just say that you put 2 identical speakers which are connected to the same power supply and a slit to create the diffraction pattern. Normally for sound when diffraction occurs, you can hear loud sounds and then soft or no sound at all. Place a microphone which is connected to a cro and move it along the length of the slit. If its destructive interference/ no sound, then the cro will show zero ampltude.
7) a) E=I(P+Q)
I=V/R (This is in terms of p because question wants voltage across P)
I=V/P Sub into E
E= V/P(P+Q)
V= EP/P+Q
b) ii) Let the parallel resistance be R
Use the equation V= (P/P+Q)E
3.6 = (2000/2000+R)6.0
R=1333.333 ohm
1/1333.33= 1/5000+ 1/ Rth
Rth=1820 ohm
8) c) Spontaneous process means the decay process is not affected by external factors such as temperature.
Hence, both the curves have a similar shape.
And for bii, how did you know that we have to use a potential divider formula? :/
 
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Sorry to bother you time and again, but could you check question 2, in ai, It's mentioned that the speed before the brakes are applied so shouldn't we use the distance 29.3? Whereas in the MS 12.8 is used? 12.8 is the distance after the brakes are applied, no? And for the same question ii, we're using s=vt. How do we know that the velocity is constant?
1.The question says that the car is travelling with speed v for 29.3m. When the brakes are applied, the car produces skid marks and during this time the deceleration is 0.85g. Basically, you can split the distance into 2 parts. The first part would be the 29.3m in which the car is travelling at constant speed v. Its constant because they say "its travelling with speed v", this means that there is no initial and final speed. The second part would be the 12.8m in which the car decelerates until rest.
2.For the 2nd part, u=v( the velocity of the car when travelling 29.3m) v=0, a=-0.85g, s=12.8
0=u^2 +2(-0.85g)(12.8)
u=14.6
3 I used the potential divider formula because normally when you do subjective questions, the questions are normally connected to each other. Plus in the question, if you were to use current, its kinda complicated. They normally will not give you the formula for no reason.
 
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can somebody explain this part II?? why is there no destructive interference ?
 

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the ans for it is highlighted
but I can't understand why won't we see a series of maxima and minima here?
 

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A rocket of mass M is travelling at a constant speed v away from a stationary observer when it instantaneously ejects one-third of its mass at a speed of 6v towards the observer. What is the new speed of the rocket?

A. 1.5 v
B. 2.0v
C. 4.5v
D. 5.0v

could someone explain how its done... the answer is 4.5v
 
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A rocket of mass M is travelling at a constant speed v away from a stationary observer when it instantaneously ejects one-third of its mass at a speed of 6v towards the observer. What is the new speed of the rocket?

A. 1.5 v
B. 2.0v
C. 4.5v
D. 5.0v

could someone explain how its done... the answer is 4.5v
Initial momentum = final momentum
let the new speed = x
Mv = 2/3(M)(x) + 1/3(M)(-6v)
x = 4.5v
 
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Hi guys! Can some please explain observing stationary waves in an air column? both open and closed?

Like what are the points we need to keep in mind for that? Also, stationary waves and musical instruments, do they even ask questions on harmonics? Ughhhhh, any help would be appreciated.
 
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Inelastic collision: a piece of plasticine of mass 0.20 kg falls to the ground and hits the ground with a velocity of 8.0 ms-1 vertically downward. It does not bounce but sticks to the ground.
1- Calculate the momentum of the plasticine just before it hits the ground.
2-State the transfers of momentum and of kinetic energy of the plasticine which occur as a result of the collision.
...WHATS THE ANS OF PART 2 ..........HELP PLZ.....WID FULL EXPLANATION!!!!
 
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