Physics: Post your doubts here!

[Suchal Riaz]

ok so the forces must be acting in equilibrium
upward forces= downward forces
f=P*A P is the atmospheric pressure
atmosphere is pushing the liquid upwards the weight of the liquid and reduced pressure is acting downwards
P*A=(0.9*P*A)+mg
mg=0.1P*A
mass of liquid is density*volume=p" *A*L where p" is density of liquid
p"ALg=0.1*P*A
cancel As on both sides
(P'')*L*g=0.1P
L=0.1P/(p"*g)

Ok i got everything. But can please explain the assumption that system is in equilibrium and upward force = download force. When the kid is pushing the water upwards the upward force must be bigger.
I think thats because we are asked to find maximum height?

 

[snowbrood]

Ok i got everything. But can please explain the assumption that system is in equilibrium and upward force = download force. When the kid is pushing the water upwards the upward force must be bigger.
I think thats because we are asked to find maximum height?

well this is in equilibrium actually what that f kid can do is just suck some air from it.the rest is air pressure. so we might think that we are drawing that liquid but no that is air pressure that is doing this



but u know what without air pressure he cant(nobody can) draw any liquid from the straw. u can do it for yourself take a jar fill half of it with liquid poke the hole at the top make sure that is air tight then try to suck some liquid u will suck some after that u wont be able to draw any liquid from straw

 

[snowbrood]

Ok i got everything. But can please explain the assumption that system is in equilibrium and upward force = download force. When the kid is pushing the water upwards the upward force must be bigger.
I think thats because we are asked to find maximum height?

oh man physics is beautiful isnt it?

 

[Suchal Riaz]

oh man physics is beautiful isnt it?

mechanics is boring. relativity is astounding. quantum mechanics is weird. string theory is mind-blowing. but the relation between them, what we call physics, is beautiful.

 

[Suchal Riaz]

oh man physics is beautiful isnt it?

mechanics is boring. relativity is astounding. quantum mechanics is weird. string theory is mind-blowing. but the relation between them, what we call physics, is beautiful.

 

[daredevil]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Physics (9702)/9702_s08_qp_4.pdf

Can someone pleasseee solve
Question 1b) why is frictional force = centripetal force//?? (according to marking scheme)
Question 4 bii) I did not understand why Va+Vb = 0 from the marking scheme.
Question 5
Question 7b ii

Plzzz someone explain these questions to me!!
Physiccss!! x_X

explaain ker do plzzz ASTAR syed1995 MustafaMotani

 

[amaz arif]

Do we have ecf in physics paper 3? I need answer quickly? Today I had a practical in my school. When measuring time, i wrote 0.0065s instead of 0.65s. I know marks will be deducted for this answer but will i get marks in the other parts which included this answer?

 

[daredevil]

yh i think we do have ecf for p3 .....
don't we??

 

[syed1995]

Do we have ecf in physics paper 3? I need answer quickly? Today I had a practical in my school. When measuring time, i wrote 0.0065s instead of 0.65s. I know marks will be deducted for this answer but will i get marks in the other parts which included this answer?

If it was School Practical.. depends on the teacher. But yes we do have ecf in CIE Practicals.. If you made that mistake in CIE you'd lose 2 marks maximum.

 

[arsalaan]

How to solve question 2 part(e) in the following paper: http://papers.xtremepapers.com/CIE/...and AS Level/Physics (9702)/9702_s08_qp_5.pdf

 

[TheStallion-Reborn]

Can someone please help me grasp the required concepts of projectile motion in AS?

 

[TheStallion-Reborn]

Can someone please help me grasp the required concepts of projectile motion in AS?

a set of notes might help :-/

 

[IGCSE O/L student]

a set of notes might help :-/

Watch the tutorials in this site: http://aplusphysics.com/courses/regents/videos/vid_index.html
N.B. there might be music at the beginning of the tutorials and at the end too, so please turn down the volume at those points

 

[Suchal Riaz]

a set of notes might help :-/

there is no reference of 'projectile' motion in physics syllabus. although you are required to understand that in such motions the velocity in one direction is constant but in perpendicular direction it is accelerated. as well as basic things such as at highest point the vertical velocity will be zero etc. thats it. old questions cover details of this chapter which is not required by current syllabus.

 

[x-gamer-x]

 

[Lama AN]

Can someone give me the answer of the end of chapter questions in the physics text book for Momentum and Deformation of solids chapters ?
I just need to compare my answers with others since we dont have the answer key in the students edition

 

[hino]

View attachment 33394

gravitational potential=GM/r
change in gravitational potential=GM/r-GM/R where R=radius of the earth + the altitude(this altitude is from the surface of the earth and not from the center) R=6400+13000=1.94*10^4
=GM(1/r-1/R) (have taken GM as common)
= (6.67 × 10-11)(6.0 x 1024)*1/(6.4 x 10^6)-1/(1.94 x 10^7) (DONT FORGET TO CONVERT km to m)
= 4.19 x 107 J kg-1 Ans

 

[x-gamer-x]

gravitational potential=GM/r
change in gravitational potential=GM/r-GM/R where R=radius of the earth + the altitude(this altitude is from the surface of the earth and not from the center) R=6400+13000=1.94*10^4
=GM(1/r-1/R) (have taken GM as common)
= (6.67 × 10-11)(6.0 x 1024)*1/(6.4 x 10^6)-1/(1.94 x 10^7) (DONT FORGET TO CONVERT km to m)
= 4.19 x 107 J kg-1 Ans

i just forgot to convert km to m
thank u

 

[hino]

you

i just forgot to convert km to m
thank u

your welcome

 

[hela]

HOW TO SOLVE http://papers.xtremepapers.com/CIE/...nd AS Level/Physics (9702)/9702_w10_qp_41.pdf
WINTER 2010 Q 2b iii