I have a row telling me the values of Force, Fi and I know that the time interval,Δt is 0.00025 seconds. However, I need to add up everything like this: ΣFi Δt. How can I accomplish this in Excel?

Note: I used impulse in the title because a lot of people seem to have the same problem and I didn't know the correct phrasing for the question.

  • 1
    Am I right in that row 1 has a bunch of numbers, row 2 should have a value incrementing by 0.00025, row 3 should have each of the cells in row 1 multiplied by their equivilent in row 2, and then sum everything in row 3? – Paul May 11 '14 at 6:11
  • Yes, Paul, that would work. It's just that I was thinking of the more complicated one line formula and couldn't figure out how to write such a formula. – raindrop May 11 '14 at 6:12
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    There probably is, but this would be the simplest way to get the answer. – Paul May 11 '14 at 6:22
A   B       A*B   Cum   Sum                     
3   0.5     2     2     C2                  
8   1.2     10    11    D2+C3                   
10  3.1     31    42    Copy the formula down the line: Copy E3 to E4:E100  
5   0.45    2     44

There are other methods too:

  • =Sumproduct(array 1, array2 ...)
  • =Sumproduct(A2:A5,B2:B5)
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