Question 916838: pleae help me. this is o confusing and i am not sure where to start. Has to be wriiiten in scientic notation
1-The number of different character passwords that caan be made with 26 letters is approximately 2.8 trillion.
2- A beam of light can travel the length of a football field in about 30 nanoseconds. Express your answer in seconds.(Hint- nano means one billionth`)
Thank you
Answer by DrBeeee(684)   (Show Source):
You can put this solution on YOUR website! One thousand is 1000 or 1 times 10^3. Agree?
In scientific notion 1000 = 1.0 x 10^3, where x means times or multiply.
I assume you know this. However, note that the 1 is written as 1.0 and the exponent 3 is the number of zeroes following the 1 in the original number 1000.
Then one million = 1,000,000 = 1.0 x 10^6, agree?
Now try 2.5 million. It is 2.5 x 1 million or 2.5 x 10^6.
Now try 25 million. It is 25 x 10^6, but we need to write the coefficient 25 as 2.5 x 10, so 25 million becomes 2.5 x 10 x 10^6 or 2.5 x 10^(6+1) or 2.5 x 10^7.
Let's do your 2.8 trillion!
A trillion is 1,000,000,000,000 or 1.0 x 10^12, so 2.8 trillion = 2.8 x 1.0 x 10^12 or 2.8 x 10^12.
Now let's do your 30 nanoseconds.
One nanosecond is, as you say one billionth of a second, or 0.000,000,001 seconds or 1.0 x 10^(-9), where the -9 exponent results from the counting, to the right, the number of decimal places we move the decimal point in order for the decimal point to be just to the right of the 1 as in 1.0.
Now 30 nanoseconds is = 30 x 1.0 x 10^(-9) or 3.0 x 10^1 x 1.0 x 10(-9) or
3.0 x 10^(-9+1) or 3.0 x 10^(-8) seconds
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