To find the correct equation for the motion of the object starting at \( x = 0 \) with an initial speed \( v_0 = 10 , \text{m/s} \) and an acceleration \( a = 3 , \text{m/s}^2 \), we can use the equation:
\[ x = x_0 + v_0 t + \frac{1}{2} a t^2 \]
Given the values:
- \( x_0 = 0 \)
- \( v_0 = 10 \)
- \( a = 3 \)
Substituting these values into the equation gives:
\[ x = 0 + 10t + \frac{1}{2}(3)t^2 \]
This simplifies to:
\[ x = 10t + \frac{3}{2} t^2 \]
Note that \(\frac{3}{2} t^2\) can also be written as \(1.5t^2\), so the equation becomes:
\[ x = 10t + 1.5t^2 \]
So, the correct response, which describes the motion of the object, is:
\(x = 10t + 1.5t^2\)