Solve Dimensional Analysis: Find Dimensions of B

AI Thread Summary
The discussion centers on solving for the dimensions of B in the equation A = B^3C^1/2, where A has dimensions L/M and C has dimensions L/T. Participants highlight the importance of correctly substituting and manipulating dimensions to isolate B. Errors in squaring and arithmetic are pointed out, emphasizing the need for clarity in grouping terms with parentheses. The correct approach involves simplifying the equation without unnecessary squaring, leading to the final dimensions of B. The conversation underscores the significance of careful dimensional analysis in physics problems.
Pajamas
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Homework Statement


A=B^3C^1/2 where A has the dimensions L/M and C has dimensions L/T. What are the dimensions of B?


Homework Equations




The Attempt at a Solution


When I worked the problem I got B=M/T but it is wrong. I'm not sure how to approach the question.
 
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You substitute the dimensions into the equation and work out what dimenstions B has to have to make the LHS match the RHS.

Please show your working.
 
So far I have B^3=TL/M^2

L/M=B^3(L/T)^1/2
with L/T then in the square root, square both sides and get T/L*L/M^2=B^3, cancel the L on bottom and one on top to get the above answer.
 
This doesn't make a lot of sense to me since B is still B^3. Am I supposed to have it look similar to the other side with TLM?
 
Pajamas said:
So far I have B^3=TL/M^2

L/M=B^3(L/T)^1/2
with L/T then in the square root, square both sides and get T/L*L/M^2=B^3, cancel the L on bottom and one on top to get the above answer.

You have several errors in this.
Squaring will produce B^6. And L^2 in L/M.
Using parentheses will make the things clearer. For you as well as for the people reading your posts.
You don't need to square. Just solve for B and put the dimensions.
 
T/L*L/M^2=T/L^2/M^2=T/(L^2M^2) ...

Yike... you need to use brackets more to group your terms.
Use square brackets to represent when you mean "dimensions of"[B^3]=(T/L)(L/M^2)=T/(M^2)

OK - but you need ... you've not finished.
(And - check your arithmetic.)
 
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