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Physics: Post your doubts here!

ad98ify

ad98ify

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GUYS! come on please reply to these queries, these are just basic phy A2 problems, isnt anyone good enough to answers these questions! i have messeged earlier bt dint get convincing replies.

''hi guys. i m having sm conceptual problems in basic concepts in chapters like gravity and electric field like :-
  • why is gravitational field strength maximum at poles rather than at equator when it should be vice versa as seen by the formula. g=GM/r^2 that is g is directly proportional to 1/r^2?
  • in electric field, why do we say that inside a point charge, potential is constant that is an equipotential surface exists?''
kindly anwers them!
 
abcde

abcde

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CaptainDanger said:
9702_s06_qp_2.pdf

9702_s06_ms_2.pdf
Click to expand...
Q1) (c) (i) Using v^2 = u^2 + 2as, v = 9.40 ms^-1.
(ii) We have to show whether or not it is justified to say that air resistance is negligible.
While the ball is travelling at a speed of 9.40 ms^-1, resistive force on it = F = crv = (3.2 x 10^-4) x (1.2 x 10^-2) x 9.40 = 3.608 x 10^-5 N.
Weight of the ball = mg = 0.015 x 9.81 = 0.14715 N.
=> Resultant force = 0.14715 - 3.608 x 10^-5 = 0.1471139 N
F = ma
=> a = 0.1471139/0.015 = 9.81 ms^-2 (approx.)
Since the acceleration of the ball is approximately equal to the acceleration of free fall g, 9.81 ms^-2, it is justified to say that air resistance is negligible.
Otherwise too, you can notice that the resistive force of 3.6 x 10^-5 N is very small as compared to the weight of the ball, so air resistance can be ignored.
 
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123456788

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guys please help me urgntly requiring i coudnt do no.6 from this file i have send the file so please help and regarding number-7 iam getting the correct answer but the naswer in the book is written 120N degree At angle of 25degree to the 50N but why cant it be also possible 25degree to 80N and its written in anticlockwise direction iam getting clockwise so please explain why its anticlockwise and no.3 of exam style question iam getting wrong answer tried several time but not getting the coorect answer so please help in that as well pleaseeeeeeeeee help as soon as possible in these 3 questions answers for 6 and 3= for 6-upstream at 78 degree to the bank
for 3-b(1) 92N (11)77NN C(1)59N (11)59N
for 3Ci havent put the image this was the question using youre answers in (b) to determine the horinzontal component of the tension in (1)RA (11)RB Coment on youre answers
if any one know one of these or 2 answrs just reply no need for 1 person to solve all the answers means what ever you know help please youre responce will be highly appreciatedvecctors doubt1.jpg
 
Unicorn

Unicorn

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abcde said:
Q1) (c) (i) Using v^2 = u^2 + 2as, v = 9.40 ms^-1.
(ii) We have to show whether or not it is justified to say that air resistance is negligible.
While the ball is travelling at a speed of 9.40 ms^-1, resistive force on it = F = crv = (3.2 x 10^-4) x (1.2 x 10^-2) x 9.40 = 3.608 x 10^-5 N.
Weight of the ball = mg = 0.015 x 9.81 = 0.14715 N.
=> Resultant force = 0.14715 - 3.608 x 10^-5 = 0.1471139 N
F = ma
=> a = 0.1471139/0.015 = 9.81 ms^-2 (approx.)
Since the acceleration of the ball is approximately equal to the acceleration of free fall g, 9.81 ms^-2, it is justified to say that air resistance is negligible.
Otherwise too, you can notice that the resistive force of 3.6 x 10^-5 N is very small as compared to the weight of the ball, so air resistance can be ignored.
Click to expand...
but isn't there a whole decimal difference?
 
CaptainDanger

CaptainDanger

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123456788 said:
guys please help me urgntly requiring i coudnt do no.6 from this file i have send the file so please help and regarding number-7 iam getting the correct answer but the naswer in the book is written 120N degree At angle of 25degree to the 50N but why cant it be also possible 25degree to 80N and its written in anticlockwise direction iam getting clockwise so please explain why its anticlockwise and no.3 of exam style question iam getting wrong answer tried several time but not getting the coorect answer so please help in that as well pleaseeeeeeeeee help as soon as possible in these 3 questions answers for 6 and 3= for 6-upstream at 78 degree to the bank
for 3-b(1) 92N (11)77NN C(1)59N (11)59N
for 3Ci havent put the image this was the question using youre answers in (b) to determine the horinzontal component of the tension in (1)RA (11)RB Coment on youre answers
if any one know one of these or 2 answrs just reply no need for 1 person to solve all the answers means what ever you know help please youre responce will be highly appreciatedView attachment 3274
Click to expand...

Q-6

Use Tan to find it...

Solved.jpg

Q-7

Its 35 degree to the 80N force... Which is its alternate answer...
 
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123456788

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for number-7 about the direction iam getting clockwise but the actual answer is anticlockwise so pleaseexplain that and also number-3 pkease as soon as possible and thanks captaindanger
 
CaptainDanger

CaptainDanger

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123456788 said:
for number-7 about the direction iam getting clockwise but the actual answer is anticlockwise so pleaseexplain that and also number-3 pkease as soon as possible and thanks captaindanger
Click to expand...

How are you taking the direction to be clockwise? I am not sure about it... Lets wait for someone else to explain it... Solution to your Exam Style 3rd Question is as followed :

Both horizontal and Vertical forces are in equilibrium...

So you have to make two equations...

Vertical :
RA cos 40 + RB cos 50 = 120

Horizontal :
RA cos 50 = RB cos 40

Solve them both simultaneously....

Hope you can do the next part too now? Answers would be same for both c (i) and c (ii) Which means horizontal forces are in equilibrium...
 
H

hassam

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My question concerns (b)(ii). Why don't we consider Rf and R while determining the required value of V2..?
 

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Mustehssun Iqbal

Mustehssun Iqbal

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Assalamu alaikum,
This question is about simple harmonic motion:
Q)A small mass attached to a spring oscillates with simple harmonic motion with amplitude of 35mm,taking 6.5s to make 20 oscillations.Calculate
a)it's angular frequencey,
b)it's maximum speed,
c)it's maximum acceleration.
Thanks in advance for your cooperation!
 
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