Physics: Post your doubts here!

[mistique_bee]

First find the weight of the object:
W = mg = 5.09 * 9.81 = 49.9N

Then find it's base area : pi * r^2 = pi * (9.4/2 * 10^-2)^2 = 6.939 * 10^-3 m^2

So pressure will be,
P = F/A
Here force exerted is the weight, so
P = 49.9./6.939*10^-3
= 7195
~7200 Pa

can u just explain this base area thing again? :/

 

[My Name]

can u just explain this base area thing again? :/

It is a cylinder right so the base is a circle.Area of a circle is pi x r^2.
They gave you dia so find radius then use this.

 

[mistique_bee]

It is a cylinder right so the base is a circle.Area of a circle is pi x r^2.

tht is okay..bt
(pi * r^2 = pi * (9.4/2 * 10^-2)^2 = 6.939 * 10^-3 m^2)
this is not getting into my head :/

 

[My Name]

tht is okay..bt
(pi * r^2 = pi * (9.4/2 * 10^-2)^2 = 6.939 * 10^-3 m^2)
this is not getting into my head :/

What part isn't? :s

It is a cylinder right so the base is a circle.Area of a circle is pi x r^2.
They gave you dia so find radius then use this.

 

[mistique_bee]

What part isn't? :s

tht complete which i pasted..like its pi*r^2..ryt? so why is 9.4 divided by 2?

 

[My Name]

tht complete which i pasted..like its pi*r^2..ryt? so why is 9.4 divided by 2?

In the question they gave you the diameter right?
BUT for area formula is PI*r^2.
D=2r haina? So to get r you divide by 2.

 

[mistique_bee]

In the question they gave you the diameter right?
BUT for area formula is PI*r^2.
D=2r haina? So to get r you divide by 2.

oh ryt..!!
im not in my senses :/ btw thanks alot

 

[My Name]

oh ryt..!!
im not in my senses :/ btw thanks alot

It was nothing.Really.
And take a break and have a Kit Kat crunchy.

 

[Rizwan Javed]

tht complete which i pasted..like its pi*r^2..ryt? so why is 9.4 divided by 2?

You are given diameter, so first you'll have to convert that to radius by halving it. Then you are to convert this radius into meters, since the diameter you are given is in centimeters, because if you are not giving to convert you can never get answer in pascals! Get it?

 

[mistique_bee]

It was nothing.Really.
And take a break and have a Kit Kat crunchy.

hahaha..ok..get me one

 

[My Name]

hahaha..ok..get me one

Excuse me? I was gonna say get me one also.

 

[mistique_bee]

You are given diameter, so first you'll have to convert that to radius by halving it. Then you are to convert this radius into meters, since the diameter you are given is in centimeters, because if you are not giving to convert you can never get answer in pascals! Get it?

yeah..thanks..u r good at explaining....

 

[mistique_bee]

Excuse me? I was gonna say get me one also.

haha..so i guess moral of the story... we both should study

 

[My Name]

haha..so i guess moral of the story... we both should study

Yeahh.

 

[mistique_bee]

Yeahh.

dont be so rude...i'll get u one...on 4th may :3

 

[Copy Cat]

 

[mistique_bee]

oct/nov 2014 p21 ques 6 part b ii

 

[ahmedish]

The magnitude of attractive magnetic force between the wires depends on the product of the currents and inversely on the distance between these two currents....product of currents = I^2 = sinosoidal and in phase ...thus f of the force varies by 2f of the current

wouldn't it be just sin^2(X) at the same frequency?
Why did it become twice the frequency?

 

[Saad the Paki]

View attachment 60415
oct/nov 2014 p21 ques 6 part b ii

R = V/I
I is 1.2 A
V is 12V
Find the total resistance from this which comes out to be 10 ohms
Now total resistance = resistance of X + resistance of Y + internal resistance
10 = 6 + Y +0.5
Y = 3.5 ohm
the resistance of X is found from the graph.

 

[sid2333]

Please help me with Q11(b)iii
http://papers.gceguide.com/A Levels/Physics (9702)/9702_w14_qp_43.pdf