To find the mass of the go-cart using the relationship \( F = ma \) (where \( F \) is force, \( m \) is mass, and \( a \) is acceleration), we can rearrange the formula to solve for mass:
\[ m = \frac{F}{a} \]
Let's use one of the data points to calculate the mass. We can use the first data point where \( F = 10 , \text{N} \) and \( a = 0.5 , \text{m/s}^2 \):
\[ m = \frac{10 , \text{N}}{0.5 , \text{m/s}^2} = 20 , \text{kg} \]
Now let's verify that this mass is consistent with the other data points.
For the second data point where \( F = 24 , \text{N} \) and \( a = 1.2 , \text{m/s}^2 \):
\[ m = \frac{24 , \text{N}}{1.2 , \text{m/s}^2} = 20 , \text{kg} \]
And for the third data point where \( F = 30 , \text{N} \) and \( a = 1.5 , \text{m/s}^2 \):
\[ m = \frac{30 , \text{N}}{1.5 , \text{m/s}^2} = 20 , \text{kg} \]
Since all three calculations give the same result, the mass of the go-cart is:
\[ \boxed{20 , \text{kg}} \]
Therefore, the correct answer is (d) 20 kg.