Questions: Question 11 (2 points) Using dimensional analysis, which one of the following equations is dimensionally correct? In these equations, x has units of meters, t has units of seconds, v has units of meters per second, and a has units of meters per second squared. t^2=x / a x=a t v=2 a x x=v / t
Transcript text: Question 11 (2 points)
Using dimensional analysis, which one of the following equations is dimensionally correct? In these equations, $x$ has units of meters, $t$ has units of seconds, $v$ has units of meters per second, and $a$ has units of meters per second ${ }^{2}$.
$t^{2}=x / a$
$x=a t$
$v=2 a x$
$x=v / t$
Solution
Solution Steps
Step 1: Understand the Units of Each Variable
\( x \) has units of meters \([m]\).
\( t \) has units of seconds \([s]\).
\( v \) has units of meters per second \([m/s]\).
\( a \) has units of meters per second squared \([m/s^2]\).
Step 2: Analyze Each Equation for Dimensional Consistency
Equation 1: \( t^2 = \frac{x}{a} \)
Left side: \( t^2 \) has units \([s^2]\).
Right side: \(\frac{x}{a} = \frac{[m]}{[m/s^2]} = [s^2]\).
Both sides have the same units \([s^2]\), so this equation is dimensionally correct.
Equation 2: \( x = a t \)
Left side: \( x \) has units \([m]\).
Right side: \( a t = [m/s^2] \cdot [s] = [m/s]\).
The units do not match, so this equation is not dimensionally correct.
Equation 3: \( v = 2 a x \)
Left side: \( v \) has units \([m/s]\).
Right side: \( 2 a x = 2 \cdot [m/s^2] \cdot [m] = [m^2/s^2]\).
The units do not match, so this equation is not dimensionally correct.
Equation 4: \( x = \frac{v}{t} \)
Left side: \( x \) has units \([m]\).
Right side: \(\frac{v}{t} = \frac{[m/s]}{[s]} = [m/s^2]\).
The units do not match, so this equation is not dimensionally correct.
Final Answer
The dimensionally correct equation is \(\boxed{t^2 = \frac{x}{a}}\).