Physics: Post your doubts here!

[Soldier313]

Thank you so much. It helped a lot.
JazakAllah Khairan.

You're welcome anytime. Am glad it did
wa iyyaki.

 

[Soldier313]

Aoa wr wb,
Does anyone have ALL or most of the A2 formulas for physics compiled (preferably topic wise) ?
I'd b really grateful if someone could upload them.
Thank you

 

[abruzzi]

Please help me solve this question.. I don't understand what to do.
Thanks

 

[sufyanalizaib]

What happens when one of the slit is closed in YOung's double slit experiment.. ??????????? kindly reply

 

[daredevil]

Someone pleaaasee explain to me the experiment to measure the gravitational field strength... paaaleeeaassee!! A star and syed1995

 

[A star]

Someone pleaaasee explain to me the experiment to measure the gravitational field strength... paaaleeeaassee!! A star and syed1995

pendilum experiment

 

[A star]

Someone pleaaasee explain to me the experiment to measure the gravitational field strength... paaaleeeaassee!! A star and syed1995

The gravitational field strength is also called the "acceleration due to gravity" (symbol "g"); and there are a number of ways you can measure that.

One way is to drop something from various heights and see how long it takes to fall. (It should be large and/or dense to reduce the effects of air friction.) Distance, time and "g" are related by this formula:

d = ½gt²

In other words:
g = 2d/t²

Record some values of "d" and "t" and plug them in.

One problem with the above is that the time periods ("t") will tend to be pretty short, and will be hard to measure accurately with a stopwatch.

Another alternative is to time the swings of a pendulum. The period of a pendulum (back & forth) is given by:

P = 2π × sqrt(L/g)

Where "L" is the length of the string. For best results, make the string very light and as long as possible, and make the "bob" fairly dense (e.g. some heavy metal). This method has the advantage that you don't have to limit yourself to just one swing of the pendulum. Measure the time of (say) 20 back-and-forth swings; then divide by the number (20) to get the duration of a single period. Then, by the above formula, you have:

g = (2π/P)²/L

 

[daredevil]

The gravitational field strength is also called the "acceleration due to gravity" (symbol "g"); and there are a number of ways you can measure that.

One way is to drop something from various heights and see how long it takes to fall. (It should be large and/or dense to reduce the effects of air friction.) Distance, time and "g" are related by this formula:

d = ½gt²

In other words:
g = 2d/t²

Record some values of "d" and "t" and plug them in.

One problem with the above is that the time periods ("t") will tend to be pretty short, and will be hard to measure accurately with a stopwatch.

Another alternative is to time the swings of a pendulum. The period of a pendulum (back & forth) is given by:

P = 2π × sqrt(L/g)

Where "L" is the length of the string. For best results, make the string very light and as long as possible, and make the "bob" fairly dense (e.g. some heavy metal). This method has the advantage that you don't have to limit yourself to just one swing of the pendulum. Measure the time of (say) 20 back-and-forth swings; then divide by the number (20) to get the duration of a single period. Then, by the above formula, you have:

g = (2π/P)²/L

mighty thanks man

 

[A star]

mighty thanks man

happy to help

 

[megamind]

thanks gary 221,but you are wrong,DAC and the serial to parallel are not the smae
check this diagram out(mobilephone flow chart)
if they are the same why are they kept seperate

 

[megamind]

seems like a tough one

 

[megamind]

ive got a simpler problem
advantages and disadvantagess of linear and nonlinear scale
this was asked in the physics scheme of work
obviously candidates are supposed to know that

i could gess some anwsers but guessing is not a good idea

 

[abruzzi]

Please help me solve this question.. I don't understand what to do.
Thanks

I'm re-posting this.. anyone?

 

[syed1995]

happy to help

P = 2π × sqrt(L/g)

never heard of that formula.. Is that in our course, that in the book? Can't we also use the dropping of a paper from certain heights? I remember doing a practical in which we made a paper cone and dropped from certain heights (50,75,100 cm) and recording time via stopwatch to determine the value of g.

 

[A star]

P = 2π × sqrt(L/g)

never heard of that formula.. Is that in our course, that in the book? Can't we also use the dropping of a paper from certain heights? I remember doing a practical in which we made a paper cone and dropped from certain heights (50,75,100 cm) and recording time via stopwatch to determine the value of g.

well first of all i can only gaurantee the first alternative to be correct as i did a practical based on it and my value of g came 9.799 which is very acuurate considering limitation i had while doing the experiment
well this formulae i learnt in O level

 

[syed1995]

well first of all i can only gaurantee the first alternative to be correct as i did a practical based on it and my value of g came 9.799 which is very acuurate considering limitation i had while doing the experiment
well this formulae i learnt in O level

Ah sweet.. Then I am glad that didn't come in O levels paper..

so can ya explain the formulae a little? what's L and P?

 

[syed1995]

I'm re-posting this.. anyone?

That A2? Link the paper... please that way we'll be able to help better

 

[A star]

Ah sweet.. Then I am glad that didn't come in O levels paper..

so can ya explain the formulae a little? what's L and P?

well L=length of string
P=i dont remember but its the average time taken by the rotation

 

[gary221]

thanks gary 221,but you are wrong,DAC and the serial to parallel are not the smae
check this diagram out(mobilephone flow chart)
if they are the same why are they kept seperate

ADC = samples the signal at regular intervals. for each sample, produces an 8- bit binary no. So DAC = will convert the binary no to a decimal no ie to an analogue signal.
Parallel to serial = takes the 8 bits from 1 sample n places them after the 8 bits from the previous sample to produce a continuous series of binary digits.
So, serial to parallel must do the opp. ie assemble the 8 bits, n pass them to the DAC for conversion into analogue. then, pass the next 8 bits to produce the next signal, n so on.
Did I say tht they both r the same??
I guess not : "The serial to parallel converter n the DAC produce an analogue signal" does not imply they r same.
And if I did say they r same, sorry, m bad!!

 

[megamind]

abruzzi

the anwser is X,
as when cos(120)=-0.5
resolve all forces towards s3(minus mens its in oppsite direction)
we get Funknoen=.5F+.5F so
funknown=F
identical spring so spring constant is same
(k)x(Eunkown)=kX
so Eunkown=X

dont thank me just find someone yo anwser
dvantages and disadvantagess of linear and nonlinear scale