Final answer:
In the equation T(t), the variable 't' typically represents time, commonly measured in seconds in physics contexts.
Step-by-step explanation:
In the equation T(t) = 72 - 42e^(-0.08t), the variable t represents the time at which the temperature T is being measured. Without more context, it's not possible to specify the exact unit for t, but based on similar scientific and physics equations, t is typically measured in units of time such as seconds, minutes, or hours. Given various references in physics contexts, such as current rising over time or acceleration, t often represents time in seconds. Furthermore, references to negative values for t indicate an event before the start of the motion, which in physics is generally considered impractical or impossible, hence such values are typically discarded.