Qualification > Sciences
Edexcel PHYSICS Doubts
Saladin:
--- Quote from: T.Q on May 29, 2010, 10:48:45 am ---ya , but u had to multiply force with cos theta
because the force is not in same direction of motion
--- End quote ---
yes, but it is force moved into the direction of force, the only force she is applying is the tension.
And she is acting in the opposite direction to it.
student:
A question from A2 ActiveBook.
(A note on the graph from the book.)
If this were a model of an automatic hand dryer circuit which requires 4.0V to operate, use the graph to work out for how long it will remain on.
The spreadsheet says the time constant is 20s, and thats what I could read off the graph.
But aint time constant = RC? And RC is 200*0.0001=0.02s, not 20s..
So.. As the minimum required voltage is 4V it won't work below that? And initial is 6V:
V = V0e-t/RC
V/V0 = e-t/20
20 ln(4/6) = -t
t = 8.109s
Wrong..
And using a lower RC would only give a shorter time, but it's 50s+.
Saladin:
--- Quote from: student on May 31, 2010, 10:02:33 am ---A question from A2 ActiveBook.
(A note on the graph from the book.)
If this were a model of an automatic hand dryer circuit which requires 4.0V to operate, use the graph to work out for how long it will remain on.
The spreadsheet says the time constant is 20s, and thats what I could read off the graph.
But aint time constant = RC? And RC is 200*0.0001=0.02s, not 20s..
So.. As the minimum required voltage is 4V it won't work below that? And initial is 6V:
V = V0e-t/RC
V/V0 = e-t/20
20 ln(4/6) = -t
t = 8.109s
Wrong..
And using a lower RC would only give a shorter time, but it's 50s+.
--- End quote ---
I regret not having the ability to answer that question. I have not finished my AS yet. I am deeply sorry.
seth99:
hey this is my frirst question on this forum.
I have A levels physics paper 5 on 9th , i have problem answering first question. if you could tell me where do i add the additional details? shall i make it as another subheading and write all additional details(as answerd in mark scheme) or shall i keep adding in the subheadings i give while answering the question.
Answer to the question number 1 is in this format given in mark scheme.
Defining the problems
Methods of data collection
Annalysing the data
safety precautions
ADDITIONAL DETAILS
Saladin:
--- Quote from: seth99 on May 31, 2010, 01:31:03 pm ---hey this is my frirst question on this forum.
I have A levels physics paper 5 on 9th , i have problem answering first question. if you could tell me where do i add the additional details? shall i make it as another subheading and write all additional details(as answerd in mark scheme) or shall i keep adding in the subheadings i give while answering the question.
Answer to the question number 1 is in this format given in mark scheme.
Defining the problems
Methods of data collection
Annalysing the data
safety precautions
ADDITIONAL DETAILS
--- End quote ---
Just post your doubt here!
Navigation
[0] Message Index
[#] Next page
[*] Previous page
Go to full version