Use of SI Units & Their Prefixes

A high-altitude balloon carries a sensor package. The data logger records the quantities shown.

Express each recorded value in its corresponding SI base unit.

The data logger records one measurement every $25\ \mathrm{ms}$.

Calculate the number of measurements recorded during $3.0\ \mathrm{min}$ of flight.

During part of the flight, the balloon rises vertically through $1.8\ \mathrm{km}$ in $4.5\ \mathrm{min}$.

Calculate its average vertical speed in $\mathrm{m\,s^{-1}}$.

A student says:

“The SI base unit for mass must be the gram because kilo is only a prefix.”

Explain why this statement is incorrect.