mujahid_e3
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Can anyone help me on these questions... if you answer it please explain to me how your got to the answer.

Thanks

1.Three hard drives spin at the following speeds. How long does it take for each of them to complete one revolution of their platters?

5400 RPM
7200 RPM
10,000 RPM

2.A hard drive with a spin speed of 7200 RPM, commences spinning at time = 0, at time = 1.326 ms what is the angle that the disk has rotated by relative to it's start position?

In degrees
In Radians

3.A computer's memory chip takes 166.6 ps to read/write data per cycle. What is the clock frequency of the memory?
Three single core micro processors have the following clock speeds. For each of them, what is the duration of a one clock cycle?

1 MHz
4 GHz
2 THz

4. An optical storage disk can store 10 PB of data, the disk is 1 mm in thickness. For every moment since you have been born, a High Definition (HD) video (1,280×720 pixels with the colour information encoded as 24 bits per pixel and a frame rate of 24 fps of your life has been recorded. How high is the stack of optical storage disks used to store the video of your life to date?
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marcusfox
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(Original post by mujahid_e3)
Can anyone help me on these questions... if you answer it please explain to me how your got to the answer.

Thanks

1.Three hard drives spin at the following speeds. How long does it take for each of them to complete one revolution of their platters?

5400 RPM
7200 RPM
10,000 RPM

2.A hard drive with a spin speed of 7200 RPM, commences spinning at time = 0, at time = 1.326 ms what is the angle that the disk has rotated by relative to it's start position?

In degrees
In Radians

3.A computer's memory chip takes 166.6 ps to read/write data per cycle. What is the clock frequency of the memory?
Three single core micro processors have the following clock speeds. For each of them, what is the duration of a one clock cycle?

1 MHz
4 GHz
2 THz

4. An optical storage disk can store 10 PB of data, the disk is 1 mm in thickness. For every moment since you have been born, a High Definition (HD) video (1,280×720 pixels with the colour information encoded as 24 bits per pixel and a frame rate of 24 fps of your life has been recorded. How high is the stack of optical storage disks used to store the video of your life to date?
Are you really too lazy to work out how long it takes something to turn once when you are given the revolutions per minute speed?

As for the rest, they are all pretty much simple mathematics.

There's a difference in strugging when reasoning through a complex question and asking for someone else to do your homework for you.
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mujahid_e3
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(Original post by marcusfox)
Are you really too lazy to work out how long it takes something to turn once when you are given the revolutions per minute speed?

As for the rest, they are all pretty much simple mathematics.

There's a difference in strugging when reasoning through a complex question and asking for someone else to do your homework for you.
thanks for your reply.. for all the questions i dont know how to work it out, thats why i posted it on here.. Maybe you can help me by telling me how to do them
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mujahid_e3
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(Original post by marcusfox)
Are you really too lazy to work out how long it takes something to turn once when you are given the revolutions per minute speed?

As for the rest, they are all pretty much simple mathematics.

There's a difference in strugging when reasoning through a complex question and asking for someone else to do your homework for you.
thanks for your reply.. for all the questions i dont know how to work it out, thats why i posted it on here.. Maybe you can help me by telling me how to do them

maybe you wouldnt mind going through them with me one by one?
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mujahid_e3
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I need the most help on q2, please can someone tell me how i do this!!

thanks
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marcusfox
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(Original post by mujahid_e3)
I need the most help on q2, please can someone tell me how i do this!!

thanks
You can easily work out the time taken to do one revolution given the RPM speed which is the number of revolutions every minute. 60 seconds per minute and 1000 milliseconds (ms) per second.

You can then calculate what fraction of one whole revolution it does in 1.326 ms.

One whole revolution is 360 degrees. You know how much of a fraction of a whole revolution it does in this time because you just calculated it, then convert to degrees to find the angle. If it completes 0.XX of a revolution, it's 0.XX x 360.

Degrees converted to radians - if you can't do this on a calculator - Google.
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mujahid_e3
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(Original post by marcusfox)
You can easily work out the time taken to do one revolution given the RPM speed which is the number of revolutions every minute. 60 seconds per minute and 1000 milliseconds (ms) per second.

You can then calculate what fraction of one whole revolution it does in 1.326 ms.

One whole revolution is 360 degrees. You know how much of a fraction of a whole revolution it does in this time because you just calculated it, then convert to degrees to find the angle. If it completes 0.XX of a revolution, it's 0.XX x 360.

Degrees converted to radians - if you can't do this on a calculator - Google.

So far i got it 0.00833 sec/rotation to do one revolution with the rpm speed. next do i do 0.00833/ 1.326 ???
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marcusfox
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(Original post by mujahid_e3)
So far i got it 0.00833 sec/rotation to do one revolution with the rpm speed. next do i do 0.00833/ 1.326 ???
It's 1.326 ps (picoseconds), so you need to get your units in order first.
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mujahid_e3
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(Original post by marcusfox)
It's 1.326 ps (picoseconds), so you need to get your units in order first.
it says 1.326ms on the question.. that in seconds is 0.001326

so do i next do 0.00833/0.001326 ??
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marcusfox
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(Original post by mujahid_e3)
it says 1.326ms on the question.. that in seconds is 0.001326

so do i next do 0.00833/0.001326 ??
Sorry, microseconds is right.
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mujahid_e3
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(Original post by marcusfox)
Sorry, microseconds is right.
ok so what do i do next?? please help and explain...

Do i do 0.00833/0.001326 get the answer and then find that in degrees?? Please help this is due in tomorrow.

thanks
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marcusfox
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(Original post by mujahid_e3)
ok so what do i do next?? please help and explain...

Do i do 0.00833/0.001326 get the answer and then find that in degrees?? Please help this is due in tomorrow.

thanks
If it takes 0.00833 seconds to do one whole revolution, how much of a revolution will it do in 0.001326 seconds?

If I can travel 60 miles in sixty minutes, how do you work out how far I travel in 20 minutes?

60/20 is 3, so you know the answer is one third.
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mujahid_e3
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(Original post by marcusfox)
If it takes 0.00833 seconds to do one whole revolution, how much of a revolution will it do in 0.001326 seconds?

If I can travel 60 miles in sixty minutes, how do you work out how far I travel in 20 minutes?

60/20 is 3, so you know the answer is one third.
thanks thats what i been saying is it 0.00833/0.001326.. the answer im getting is 39/245 now do i convert this to degrees?
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mujahid_e3
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anyone?? I need to get it finished today plz
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stefnic
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Did you manage to get this done?
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