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In equation y = x^2 cos^2 2p (ß?/a) , the units of x, a , ß are m , s^-1 ans (ms-1)^-1 respectively. The units of y and ? are ....?

Swati , 12 Years ago
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Askiitians Tutor Team

To determine the units of \( y \) and \( ? \) in the equation \( y = x^2 \cos^2 \left( \frac{\beta ?}{a} \right) \), we need to analyze the components of the equation and how they relate to each other. Let's break it down step by step.

Understanding the Variables

In the given equation, we have:

  • x: This variable has units of meters (m).
  • a: This variable has units of seconds inverse (s-1).
  • β: The units of β are given as (m s-1)-1, which simplifies to s m-1.

Analyzing the Equation

The equation can be rewritten to focus on the units:

1. The term \( x^2 \) has units of \( m^2 \) since it is the square of \( x \).

2. The cosine function, \( \cos^2 \left( \frac{\beta ?}{a} \right) \), is dimensionless. This means that the argument of the cosine function must also be dimensionless.

Determining the Units of the Argument

For the argument \( \frac{\beta ?}{a} \) to be dimensionless, the units of \( \beta ? \) must match the units of \( a \). Let's analyze this:

  • Units of \( a \): s-1
  • Units of \( \beta \): s m-1

Now, substituting the units of \( \beta \) into the argument:

Units of \( \beta ? = (s \cdot m^{-1}) \cdot ? \

Setting this equal to the units of \( a \):

Units of \( \beta ? = s m^{-1} ? = s^{-1}.

Solving for the Units of ?

To isolate the units of \( ? \), we can rearrange the equation:

\( s m^{-1} ? = s^{-1} \)

Dividing both sides by \( s m^{-1} \):

\( ? = \frac{s^{-1}}{s m^{-1}} = m \cdot s^{-2} \)

Final Units for y

Now that we have determined the units of \( ? \), we can find the units of \( y \):

Since \( y = x^2 \cos^2 \left( \frac{\beta ?}{a} \right) \), and knowing that \( \cos^2 \) is dimensionless, the units of \( y \) will simply be the units of \( x^2 \):

Thus, the units of \( y \) are \( m^2 \).

Summary of Units

  • Units of y: m2
  • Units of ?: m s-2

In summary, we have determined that the units of \( y \) are square meters (m2), and the units of \( ? \) are meters per second squared (m s-2). This analysis shows how the relationships between different variables can help us derive the necessary units in a given equation.

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