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Units And Measurement

Question
CBSEENPH11017677
Wired Faculty App

How large is a torque needed to accelerate a wheel of moment of inertia, I = 2kgm2 from rest to 30rps in 20s? 

Solution

Here, we have
 straight ϖ subscript 0 equals 0 space straight ϖ equals 30 space rps space equals space 60 space rad divided by straight s space straight t equals 20 straight s comma space straight I equals 2 space kgm squared
Now, using the equation of rotational motion, we have
                 straight ϖ equals straight ϖ subscript 0 plus straight alpha space straight t
therefore space space straight alpha space equals fraction numerator straight ϖ minus straight ϖ subscript 0 over denominator straight t end fraction space or space space straight alpha space equals space fraction numerator 60 straight pi minus 0 over denominator 15 end fraction equals 4 straight pi space rad divided by straight s squared Now comma space space space straight tau equals space Iα space space space space space equals 2 cross times 4 straight pi space space space space space equals 8 straight pi space Nm  

Some More Questions From Units and Measurement Chapter

Can we use different units to measure same physical quantity?

To measure a physical quantity X, the unit U is repeatedly used for n times. What is the magnitude of physical quantity?

Does the numerical factor in the quantitative measurement depend on the system of unit used?

Is one unit sufficient to measure a physical quantity?

Can a physical quantity have two or more units? Give example.

What are fundamental quantities?

How many fundamental quantities are there in mechanics?

How many fundamental quantities are there in Physics?

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