Solving a Physics Problem: Finding the Right Units

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SUMMARY

This discussion focuses on the importance of dimensional analysis in physics, specifically in determining the correct units for velocity calculations. The example provided involves the expression \sqrt{\frac{940N/m}{0.038kg}}*(0.25m), which simplifies to 39m/s. The analysis shows that when using base units, Newtons (N) can be expressed as kg m s^-2, allowing for proper cancellation and simplification of units. Ultimately, the final units derived from the expression are \sqrt{N}*m, emphasizing the necessity of maintaining unit consistency for accurate results.

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  • Ability to manipulate square roots in unit expressions
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i just need help with finding the units to a physics problem at the end. some examples...


[tex]\sqrt{\frac{940N/m}{0.038kg}}*(0.25m)[/tex]

it comes out to 39m/s.

i know that since it's velocity, it should always be m/s. but there are some question that i don't really know what the final units should be.

without the numbers...
[tex]\sqrt{\frac{N/m}{kg}}*(m)[/tex]
it doesn't seem like anything can be canceled out because the units are being sqrtrooted.
 
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Put Newtons in base units, N = kg m s^-2 and you'll see everything inside the square root cancels out, besides the s^-2.
 



When solving a physics problem, it is important to pay attention to the units involved in the given values and the final answer. Units act as a guide to ensure that the calculations are done correctly and the final answer is in the correct form. In the given example, the units for force are Newtons (N) and for mass are kilograms (kg). To find the units for the final answer, we can use the method of dimensional analysis.

First, let's look at the given expression: \sqrt{\frac{940N/m}{0.038kg}}*(0.25m). We can see that the numerator has units of N/m (force per unit length) and the denominator has units of kg (mass). When we take the square root, the units of N/m and kg will also be square rooted. This means that the final units for the expression will be \sqrt{\frac{N}{m}}*\sqrt{kg}*m. To simplify this, we can rewrite it as \sqrt{N}*m.

Now, let's consider the example without numbers: \sqrt{\frac{N/m}{kg}}*(m). Here, we can see that the units for force are still N/m and for mass are kg. When we take the square root, the units will be \sqrt{\frac{N}{m}}*\sqrt{kg}. This cannot be simplified any further as the units are being square rooted. Therefore, the final units for this expression will be \sqrt{N}*m.

In conclusion, when solving a physics problem, it is important to pay attention to the units involved and use dimensional analysis to determine the units for the final answer. In some cases, the units may not cancel out and the final answer will have a combination of units. However, as long as the units are correct and consistent, the final answer will be accurate.
 

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