To find the population of the city in the year 2000 using the given exponential function \( p(t) = 28000(1.02)^t \), we can evaluate it at \( t = 0 \) because \( t = 0 \) corresponds to the year 2000.
Substituting \( t = 0 \) into the equation:
\[ p(0) = 28000(1.02)^0 \]
Since \( (1.02)^0 = 1 \), we have:
\[ p(0) = 28000 \cdot 1 = 28000 \]
Therefore, the population in the year 2000 was 28,000.