Whitney in KY Posted March 15, 2009 Share Posted March 15, 2009 My daughter has an algebra 1 problem we are stuck on: S=The square root of g times d Where g is 9.8 and d=1000 We get stuck about half way through. Anyone know how to tackle this? TIA! Whitney Quote Link to comment Share on other sites More sharing options...
athena1277 Posted March 15, 2009 Share Posted March 15, 2009 I could help with this, but I need clarification: Is it sqrt(9.8) times 1000, or sqrt(9.8*1000)? It makes a difference where what you are taking the square root of. Quote Link to comment Share on other sites More sharing options...
Whitney in KY Posted March 15, 2009 Author Share Posted March 15, 2009 is correct. Sorry, I should have clarified that. Thanks! Quote Link to comment Share on other sites More sharing options...
athena1277 Posted March 15, 2009 Share Posted March 15, 2009 Ok, so the problem should go like this: S=sqrt(9.8*1000) S=sqrt(9800) S=98.99 There are a lot of decimals, you'll have to see what the particular book is asking to round to. Personally, I'd leave it as above. BTW, this isn't something you can figure without a calculator, unless you are a genius!:D HTH! Quote Link to comment Share on other sites More sharing options...
forty-two Posted March 15, 2009 Share Posted March 15, 2009 Where g is 9.8 and d=1000I'm guessing that g is gravity - 9.8 m/s^2 - and d is distance - 1,000 m. S=The square root of g times dIs it S = sqrt(g*d), or S = sqrt(g)*d? I'm guessing that it's the former, as at least that yields units that make sense (m/s - velocity), but I admit I'm confused, as neither one looks like a formula I'm familiar with. Assuming the problem is where something is dropped 1,000m above the earth, and you want to know at what velocity said object hits the ground, the given equation - S = sqrt(g*d) - is close enough for Alg I work, I guess (it should be S = sqrt(2g*d)). At any rate, to solve it you'd just: *plug in your values for g&d: S = sqrt(9.8*1000) *and do the calculation: S = sqrt(9.8*10*100) =sqrt(98)*sqrt(100) =~9.9*10 =~99 Quote Link to comment Share on other sites More sharing options...
Whitney in KY Posted March 15, 2009 Author Share Posted March 15, 2009 Let me clarify. Sorry I didn't do this to start with. The problem goes like this: The speed, s (in meters per second) at which a tsunami moves is determine by the depth, d (in meters) of the ocean. s=sqrt (g times d), where g is 9.8 meters per second. ***Find the speed of a tsunami in a region of the ocean tat is 1000 meters deep. Write the result in simplified form.*** The answer in the back of the book says: 70 sqrt (2) I think I am writing that right, I would say "Seventy square root 2" Quote Link to comment Share on other sites More sharing options...
forty-two Posted March 15, 2009 Share Posted March 15, 2009 Let me clarify. Sorry I didn't do this to start with. The problem goes like this: The speed, s (in meters per second) at which a tsunami moves is determine by the depth, d (in meters) of the ocean. s=sqrt (g times d), where g is 9.8 meters per second. ***Find the speed of a tsunami in a region of the ocean tat is 1000 meters deep. Write the result in simplified form.*** Oh, ok. Learned something new =). The answer in the back of the book says: 70 sqrt (2)Ok, I see what they did. Instead of approximating sqrt(98), like I did, they separated it into sqrt(49*2). So the whole problem would go like: S = sqrt(9.8 * 1000) = sqrt(9.8*10*100) = sqrt(98)*sqrt(100) = sqrt(49*2)*10 = sqrt(49)*sqrt(2)*10 = 7*sqrt(2)*10 =70sqrt(2) m/s HTH Quote Link to comment Share on other sites More sharing options...
Perry Posted March 15, 2009 Share Posted March 15, 2009 Here's how I think about this problem: √(9.8*1000)= √(9.8*10*10*10)= I see that I can take out 10*10 so 10√(9.8*10)= 10√98 10√(49*2)= Since 49 is a perfect square I can take out 7 so 7*10√2= 70√2 Quote Link to comment Share on other sites More sharing options...
Whitney in KY Posted March 15, 2009 Author Share Posted March 15, 2009 So very much! I appreciate your help! We get it now. Whitney Quote Link to comment Share on other sites More sharing options...
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