Final answer:
Caffeine is a substantially less powerful stimulant than cocaine.
Step-by-step explanation:
The drug or class of drugs that is a substantially less powerful stimulant than cocaine is caffeine. While cocaine is a tropane alkaloid and a highly potent stimulant drug, caffeine is a much milder stimulant and is widely consumed in beverages like coffee and tea. Although caffeine can increase alertness and arousal, its potency is significantly lower compared to cocaine.