Final answer:
The maximum time you can crank the 15 kW generator engine before it must cool down is 1 hour.
Step-by-step explanation:
To determine the maximum time the 15 kW generator engine can be cranked before it must cool down, we need to consider the power and efficiency of the engine. Since the power of the generator is 15 kW, we can convert this to watts by multiplying it by 1000, giving us 15000 W. Assuming the generator has an efficiency of 100%, we can use the equation Power = work / time to find the maximum time, where work = power × time. Rearranging the equation, we have time = work / power. Substituting the values, we get time = 15000 W / 15000 W = 1 hour. Therefore, the maximum time you can crank the 15 kW generator engine before it must cool down is 1 hour.