Physics: Post your doubts here!

[Asheeta]

didnt understand this part

what has been found is the min possible area of the cr0ss-section. what is needed is the max area of cross-section,
so to find the max area of cross-section just take the original area and subtract the min area from it.
you'll obtain the max area.
hope it is clear, if not do not hesitate to ask.

 

[PinkRhinos]

so max height reached by ball is when v = 0 m/s
so find the max height reached using (v^2) = (u^2) + 2as
0 = (11 sin 45)^2 + (2*-10*s)
s = 3.025 m
so ball goes just over the wall.
Hope it is clear.

Can you explain ""(2*-10*s)"" ? and thanks

 

[Asheeta]

Can you explain ""(2*-10*s)"" ? and thanks

well infact it is 2 (times) negative 10 (times) S
S is the displacement
Or if you want it is like : 2(-10)(s) , it is in the form 2as, 2 multiplied by a multiplied by s

 

[HorsePower]

ASA
can anyone please explain why gravitational potential is always negative inside the gravitational field?

 

[geek101]

ASA
can anyone please explain why gravitational potential is always negative inside the gravitational field?

To move the unit mass away from the gravitational field in the first place, +ve work is done. So when the reverse is done, ie. unit mass is moved from infinity, where the g.potential is zero to a point inside the gravitational field, work is gotten out, or -ve work is done. Or lets say that when ur moving from max gravitational field...to min...to zero >> infinity, the gp is poisitve. so if you go in the opp direction which is the correct definition, the gp will become more and more negative. hope that helps

 

[MariamHASAN]

Can u tell me the Uncertainity topic required in physics and how the questions are solved!

 

[HorsePower]

To move the unit mass away from the gravitational field in the first place, +ve work is done. So when the reverse is done, ie. unit mass is moved from infinity, where the g.potential is zero to a point inside the gravitational field, work is gotten out, or -ve work is done. Or lets say that when ur moving from max gravitational field...to min...to zero >> infinity, the gp is poisitve. so if you go in the opp direction which is the correct definition, the gp will become more and more negative. hope that helps

thnx alot

 

[Kumkum]

Please explain question number 3 (e)(ii):
question paper:http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Physics (9702)/9702_w04_qp_2.pdf and
marking scheme: http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Physics (9702)/9702_w04_ms_2.pdf

 

[Khunkar]

Help me on no.5 b ) : which direction is the wave travelling?
http://www.xtremepapers.com/papers/...and AS Level/Physics (9702)/9702_w02_qp_2.pdf

 

[queen of the legend]

Please explain question number 3 (e)(ii):
question paper:http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Physics (9702)/9702_w04_qp_2.pdf and
marking scheme: http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Physics (9702)/9702_w04_ms_2.pdf

principle of conservation of momentum states that provided no external force act , the momentum of a sytem is conserved.
since in the system of ball and earth , a force of gravitation is acting tht causes acceleration or change in momentum, the law of conservation does not apply.

 

[queen of the legend]

Help me on no.5 b ) : which direction is the wave travelling?
http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Physics (9702)/9702_w02_qp_2.pdf

you did not mention what part of question 5 you did not understand. anyhow i will explain the first one in thich it says that T2 lags behind a phase diff. 60 degrees
there is a rule : phase diff.(theta) = (t/T) X 360 . thetais given as 60 degrees. T is time period for one oscilation and t is difference of T between two waves.
you sould substitute for t and the answer will give you the amount by which T2 is behind T1.
simply draw T2 now !

i hope you understood

 

[D0cEngi]

Can u tell me the Uncertainity topic required in physics and how the questions are solved!

Plz mention any question...We will then be able to solve it and explain it to u....

 

[Khunkar]

principle of conservation of momentum states that provided no external force act , the momentum of a sytem is conserved.
since in the system of ball and earth , a force of gravitation is acting tht causes acceleration or change in momentum, the law of conservation does not apply.

Doesn't the principle say that two objects needs to collide? If it is so, can we say since ball is not in contact with any other object, the principle doesn't support the answer?

 

[Kumkum]

principle of conservation of momentum states that provided no external force act , the momentum of a sytem is conserved.
since in the system of ball and earth , a force of gravitation is acting tht causes acceleration or change in momentum, the law of conservation does not apply.

thnx!

 

[D0cEngi]

Help me with the uncertainity thing in ppr 3.....asap..!!!

 

[Khunkar]

Anybody help me on, qno. 5 c ii )
http://www.xtremepapers.com/papers/...and AS Level/Physics (9702)/9702_w05_qp_2.pdf
Thanks.

 

[Silent Hunter]

http://www.xtremepapers.com/papers/...nd AS Level/Physics (9702)/9702_s10_qp_21.pdf​

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some help here required people ... thank you very much​

need to clear some concepts​

so need some explanations to the following​

Q5 (c)​

​

thanks again ​

 

[champ-student]

http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Physics (9702)/9702_s10_qp_21.pdf


some help here required people ... thank you very much
need to clear some concepts
so need some explanations to the following
Q5 (c)

thanks again

(c) (i) arrows through P and N in correct directions
(ii) torque = force × perpendicular distance (between forces)
= 1.6 × 10
–19
× 5.0 × 10
4
× 2.8 × 10
–10
× sin30
= 1.1 × 10
–24
N m

 

[Silent Hunter]

(c) (i) arrows through P and N in correct directions

thanks but what are the correct directions ?

 

[Khunkar]

http://www.xtremepapers.com/papers/CIE/Cambridge International A and AS Level/Physics (9702)/9702_s10_qp_21.pdf


some help here required people ... thank you very much
need to clear some concepts
so need some explanations to the following
Q5 (c)

thanks again

5 c i) I think the force on P is in direction to the applied electric field whereas on N is opposite in direction to the applied electric field because since the direction of electric field is from +ve to -ve, P(which is +ve in charge) should be attracted to the -ve end. Similar concept applies to N.
ii) V/d = F/q
5 * 10^4(Given) = F / 1.6 * 10^-19
F = 8 * 10^-15
For torque, Torque = F * perpindicular distance between the two force of a couple. So,
Torque = 8 * 10^-15 * (2.8 * 10^-10 * sin 30)
= 1.12 * 10^-24

Hope I helped you out.