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i am out.....Thought Blocker kay ander Shaitaan araa hay....Lol wht u guys r doing?
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i am out.....Thought Blocker kay ander Shaitaan araa hay....Lol wht u guys r doing?
Short answer, because the time taken with each speed is different.
Short answer, because the time taken with each speed is different.
Let's do the math behind this - suppose the distance traveled with both speeds is denoted by "s".
Suppose the time taken at 600 kmph = t(1).
Then, since Speed = Distance/Time, we can write
600 = s/t(1)
So that
t(1) = s/600
Similarly, let's do the same for the other speed. The distance traveled is still "s", the speed = 400 kmph, and the time taken to traverse this distance = t(2). So:
400 = s/t(2)
So that
t(2) = s/400
The average speed is the total distance traveled dividing by the time taken (the average velocity is different - it is equal to total displacement divided by time taken).
= (Total Distance traveled)/(Time taken to cover that distance).
Since the plane travels a distance "s" in one direction and returns the same distance "s", the total distance traveled = s+s = 2s.
The time taken = t(1) + t(2) = s/400 + s/600 = 3s/1200 + 2s/1200 = 5s/1200 = s/240
Therefore, the average speed = 2s/(s/240) = 480 kmph = C.
Thank You!!!17)
F is proportional to v^2
=> F = k*v^2
800 = k *(20)^2
k = 2
Use this value of k to find F when v = 40m/s
Then use P = Fv
30)
d*sin@ = n*lambda
(1.00×10^–6) sin (70/2) = (1) (lambda)
lambda = 574 nm
I don't know 18 either. And i'm not very good with explanations, sorry.
I'm extremely grateful to you for giving your time in answering the questions, thank you.Q35)
When the switch S is closed, a current is allowed to flow through the circuit. When the current flows through the circuit, a potential difference is produced across the resistor R. This means that energy is lost in the resistor.
Also, when current goes through the internal resistance of the battery, energy is lost in that internal resistance. Therefore, some of the battery's energy and potential difference is lost in the battery itself.
However, we have to remember the definition of e.m.f - it is the total work done by the battery in driving one coulomb of current around the complete circuit. This work includes the work done by the battery in pushing the current through the internal resistance also, and it is equal to the voltage across the battery when the circuit is not closed (if you put a voltmeter across the battery when the switch S is open, the voltage measured is the rating of the battery AND the e.m.f. value).
Suppose you take internal resistance and separate it from the cells in the battery, then the energy lost in the internal resistance + the energy lost in resistor R is still equal to the e.m.f.
Remember, e.m.f. is the work done by the cells in the battery to push one coulomb through the complete circuit. They will do the same work whether there is internal resistance or not, so the e.m.f. does not change in the circuit because the cells can be assumed to be separate from the internal resistance.
So, A and B are eliminated; e.m.f. does not change at all.
But because a battery = cells + internal resistance, when S is closed, current flows through the circuit and energy is lost in the internal resistance. Also, there is a loss in potential across the internal resistance, so there is a loss in potential across the battery. Therefore, the potential across the battery changes because energy is lost in the internal resistance = C.
Note: if energy is lost in any resistance, it is because work is done against that resistance (suppose you are pushing a box on the ground, friction is the resistance, and you need to do some work against that friction resistance. Your muscles are the potential pushing the current, and some of that energy is lost when you work against friction).
I want you to check out my signature.. Its really helpful
ote="Zepudee, post: 814292, member: 97182"]http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_w12_qp_12.pdf
19)w03 Q19 ?? anyone
GO* TO CHEMISTRY THREADDoes anybody have explanations for chemistry as well?
Link please ._.9702_w10_qp_12.pdf
Q 8 and 9 thank you
8)9702_w10_qp_12.pdf
Q 8 and 9 thank you
Thank you so much. I did get Q 9. But Q8 main I have one issue, for the second equation why didn't we use the the distance YZ instead of XZ, if we do, kiya uss se answer same aaye ga?8)
lets see the motion in XY
initial velocity at x=v1
final velocity at y=v2
average velocity=distance/time
(V1+V2)/2=40/12 equation 1
simplifying it we get V1+V2=6.67
now consider motion in XZ
initial velocity at x=v1
final velocity=v3
V1+V2/2=(40+40)/(12+6)
simplifying it we get V1+V3=8.89 equation 2
subtract equation 1 from 2
i mean equation 2-equation 1
V1 is cancelled and we get V3-V2=2.22
since acceleration is constant so
acceleration in yz = acceleration in xz
= change in velocity/time
=2.22/6
=0.37
9)
initial momentum of the ball is 2mv before collision... if collision was perfectly elastic one, all the momentum would have been gained by the ball... and this would have made the change in the momentum equal to 4mv.. 2mv-(-2mv)... now it is given that collision is inelastic, it will lose some of its momentum to the wall.. so now change in momentum will be less than 4mv but cant be less than the initial momentum... so the answer is C.. i think you cannot verify the answer by the calculations...
Try out urself dude and then answerThank you so much. I did get Q 9. But Q8 main I have one issue, for the second equation why didn't we use the the distance YZ instead of XZ, if we do, kiya uss se answer same aaye ga?
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