# i Need help for isaacphysics assignment please!!!!! ASAP!

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1) A current of 5.5mA5.5mA is flowing through a resistance of 220kΩ Find the potential difference (in volts) across the resistance.

5.5 mA =5,500,000 A , 220 kohms =220,000 ohms. P.D= IxV, = 5,500,000 X 220,000 = 1.21 X 10^12 Volts

i got : 1.21x10^12. but it says sig figs are incorrect? WHERE have i gone wrong???

5.5 mA =5,500,000 A , 220 kohms =220,000 ohms. P.D= IxV, = 5,500,000 X 220,000 = 1.21 X 10^12 Volts

i got : 1.21x10^12. but it says sig figs are incorrect? WHERE have i gone wrong???

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#2

(Original post by

1) A current of 5.5mA5.5mA is flowing through a resistance of 220kΩ Find the potential difference (in volts) across the resistance.

5.5 mA =5,500,000 A , 220 kohms =220,000 ohms. P.D= IxV, = 5,500,000 X 220,000 = 1.21 X 10^12 Volts

i got : 1.21x10^12. but it says sig figs are incorrect? WHERE have i gone wrong???

**poonshark**)1) A current of 5.5mA5.5mA is flowing through a resistance of 220kΩ Find the potential difference (in volts) across the resistance.

5.5 mA =5,500,000 A , 220 kohms =220,000 ohms. P.D= IxV, = 5,500,000 X 220,000 = 1.21 X 10^12 Volts

i got : 1.21x10^12. but it says sig figs are incorrect? WHERE have i gone wrong???

Firstly, if you have transcribed the problem correctly, then represents ; the correct way to read is 'milli-amperes'. If you instead meant to type , then your interpretation would be correct.Your interpretation of the resistance is correct and you can now use Ohm's law, to calculate the potential difference.

(2 significant figures)

I think Isaac Physics wants you to quote your answer to two significant figures, as this is the minimum number of significant figures that have been given to you in the question.

I hope that this has been helpful.

Smithenator5000.

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(Original post by

Hello there,

Firstly, if you have transcribed the problem correctly, then represents ; the correct way to read is 'milli-amperes'. If you instead meant to type , then your interpretation would be correct.Your interpretation of the resistance is correct and you can now use Ohm's law, to calculate the potential difference.

(2 significant figures)

I think Isaac Physics wants you to quote your answer to two significant figures, as this is the minimum number of significant figures that have been given to you in the question.

I hope that this has been helpful.

Smithenator5000.

**Smithenator5000**)Hello there,

Firstly, if you have transcribed the problem correctly, then represents ; the correct way to read is 'milli-amperes'. If you instead meant to type , then your interpretation would be correct.Your interpretation of the resistance is correct and you can now use Ohm's law, to calculate the potential difference.

(2 significant figures)

I think Isaac Physics wants you to quote your answer to two significant figures, as this is the minimum number of significant figures that have been given to you in the question.

I hope that this has been helpful.

Smithenator5000.

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#4

(Original post by

Thank you, that helps a lot! I didn't realise the unit was milli-amperes

**poonshark**)Thank you, that helps a lot! I didn't realise the unit was milli-amperes

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(Original post by

You're very welcome All the best with the assignment.

**Smithenator5000**)You're very welcome All the best with the assignment.

I am given this table-

and these questions -

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#6

(Original post by

Sorry to bother you but there is a question on my assignment which i have never been taught, i am a bit confused how it works?

I am given this table-

and these questions -

**poonshark**)Sorry to bother you but there is a question on my assignment which i have never been taught, i am a bit confused how it works?

I am given this table-

and these questions -

I am surprised that you haven't been taught this; it is pretty important. For the first part, it wants you to be able to

**write the units**on the left in an

**equivalent form**. All of these units can be expressed in terms of the seven

**'base units'**. These are:

**source:**http://physics.nist.gov/cuu/Units/units.html

You can find the

**base unit representations**by using a formula that you know and

**treating the units like variables**. For example, the

**Newton**is a unit of

**force**. One equation involving

**force**is

**, a form of**

**Newton's Second Law**. This equation implies that

**, where**

**represents the units of quantity**

**. We can use this to find the**

**base unit representation**of the

**Newton**.

You would enter this into

**Isaac Physics**by telling it the power of each unit it lists.

Once again, I hope this has been helpful and please do not worry about bothering me.

Smithenator5000.

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(Original post by

Hello there,

I am surprised that you haven't been taught this; it is pretty important. For the first part, it wants you to be able to

You can find the

You would enter this into

Once again, I hope this has been helpful and please do not worry about bothering me.

Smithenator5000.

**Smithenator5000**)Hello there,

I am surprised that you haven't been taught this; it is pretty important. For the first part, it wants you to be able to

**write the units**on the left in an**equivalent form**. All of these units can be expressed in terms of the seven**'base units'**. These are:**source:**http://physics.nist.gov/cuu/Units/units.htmlYou can find the

**base unit representations**by using a formula that you know and**treating the units like variables**. For example, the**Newton**is a unit of**force**. One equation involving**force**is**, a form of****Newton's Second Law**. This equation implies that**, where****represents the units of quantity****. We can use this to find the****base unit representation**of the**Newton**.You would enter this into

**Isaac Physics**by telling it the power of each unit it lists.Once again, I hope this has been helpful and please do not worry about bothering me.

Smithenator5000.

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#8

(Original post by

Thanks again! I'll give this a go.

**poonshark**)Thanks again! I'll give this a go.

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(Original post by

You're welcome. Do not hesitate to ask for help if required.

**Smithenator5000**)You're welcome. Do not hesitate to ask for help if required.

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#10

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Hi , i have to find the area under the line in the graph. I don't understand where i gone wrong? i got (25x5)/2 + 25x1 = 87.5 - 88 to 2 sf. This is the graph i have.

**poonshark**)Hi , i have to find the area under the line in the graph. I don't understand where i gone wrong? i got (25x5)/2 + 25x1 = 87.5 - 88 to 2 sf. This is the graph i have.

Notice that the

**y-axis**(showing current in amperes)

**starts from**

**, as opposed to**

**. I believe that the question wants you to consider the area which**

**includes**that which has been

**omitted from the graph**. Here is a diagram of what I am trying to describe.

You can now try calculating the area of this. Please reply if this doesn't work.

Smithenator5000.

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(Original post by

Hello there,

Notice that the

You can now try calculating the area of this. Please reply if this doesn't work.

Smithenator5000.

**Smithenator5000**)Hello there,

Notice that the

**y-axis**(showing current in amperes)**starts from****, as opposed to****. I believe that the question wants you to consider the area which****includes**that which has been**omitted from the graph**. Here is a diagram of what I am trying to describe.You can now try calculating the area of this. Please reply if this doesn't work.

Smithenator5000.

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#12

(Original post by

Of course! i understand now. Thanks i wouldn't have realised that. Are you a physics teacher or something?

**poonshark**)Of course! i understand now. Thanks i wouldn't have realised that. Are you a physics teacher or something?

**source: http://www2.ccsd.ws/sbfaculty/team8e...g%20Points.htm**

I am actually an upper sixth student at the moment, so I have just completed my AS in physics and am now studying for full A-levels in physics, maths and further maths. Where are you at?

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You are very welcome. It is always worth checking for things like that. Personally, I think they should have indicated the transposed scale with a scribble on the y-axis like so:

I am actually an upper sixth student at the moment, so I have just completed my AS in physics and am now studying for full A-levels in physics, maths and further maths. Where are you at?

**Smithenator5000**)You are very welcome. It is always worth checking for things like that. Personally, I think they should have indicated the transposed scale with a scribble on the y-axis like so:

**source:**[/b]I am actually an upper sixth student at the moment, so I have just completed my AS in physics and am now studying for full A-levels in physics, maths and further maths. Where are you at?

Also how would you go about calculating the area under these two non-linear graphs? I tried to estimate them but i failed

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#14

(Original post by

i have just started AS level. i was assigned loads physics homework on isaac physics which is due in on monday. I am studying maths ,physics, economics , and chemistry for AS.

**poonshark**)i have just started AS level. i was assigned loads physics homework on isaac physics which is due in on monday. I am studying maths ,physics, economics , and chemistry for AS.

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Cool. Are you enjoying it so far? I suppose that the physics homework is supposed to be a prerequisite task. Otherwise I find it strange that your teacher assigned it to you, given that you claim that they haven't taught you some of it.

**Smithenator5000**)Cool. Are you enjoying it so far? I suppose that the physics homework is supposed to be a prerequisite task. Otherwise I find it strange that your teacher assigned it to you, given that you claim that they haven't taught you some of it.

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#16

(Original post by

Yeah we have't been given any lessons yet at all, but we need to have these assignements completed by the first lesson on monday. also how would you go about calculating the area under these non linear graphs? i tried to estimate them but i failed

**poonshark**)Yeah we have't been given any lessons yet at all, but we need to have these assignements completed by the first lesson on monday. also how would you go about calculating the area under these non linear graphs? i tried to estimate them but i failed

**calculating the combined area**of a

**trapezium**(up to

**) and a**

**rectangle**(from

**and onward). For the second and third one,**

**exact areas**can be calculated by

**integration**(though I expect that you won't have learned about that yet). To do this however, you need to know the exact equations of the lines and besides, A-level physics does not expect this knowledge. The traditional way to estimate the areas is by

**splitting the area**up into

**trapeziums**and

**summing their areas**. For each of these graphs, you should be cautious, as the some of the units have

**prefixes**. If you have already tried this, could you post your calculations?

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(Original post by

It depends on what information you have about them. The first one could be estimated by

**Smithenator5000**)It depends on what information you have about them. The first one could be estimated by

**calculating the combined area**of a**trapezium**(up to**) and a****rectangle**(from**and onward). For the second and third one,****exact areas**can be calculated by**integration**(though I expect that you won't have learned about that yet). To do this however, you need to know the exact equations of the lines and besides, A-level physics does not expect this knowledge. The traditional way to estimate the areas is by**splitting the area**up into**trapeziums**and**summing their areas**. For each of these graphs, you should be cautious, as the some of the units have**prefixes**. If you have already tried this, could you post your calculations?
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#18

(Original post by

so because some have prefixes, would you have to convert the values back into standard units before calculating e.g convert uS into seconds ?

**poonshark**)so because some have prefixes, would you have to convert the values back into standard units before calculating e.g convert uS into seconds ?

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**poonshark**)

so because some have prefixes, would you have to convert the values back into standard units before calculating e.g convert uS into seconds ?

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#20

(Original post by

here is the graphs again in a more complete view , no extra infomation has been given

**poonshark**)here is the graphs again in a more complete view , no extra infomation has been given

You can then calculate the area of each trapezium and add them together to get the total area. You can make the estimate more accurate by increasing the number of trapeziums.

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