What temperature is required to transfer waste heat to the environment for a heat engine to be 100 percent efficient?

An infinite temperature

Explanation:

The efficiency of an engine is defined as:

where

is the temperature at which heat enters the engine

is the temperature of the environment, to which the engine exhausts heat

From the formula, we see that for an engine to be 100% efficient, the fraction

must be equal to zero. Since the value of is never zero (the temperature is expressed in Kelvin, and the temperature of the environment can never be exactly 0 K), the only possibility for that to occur is that the temperature at which heat enters the engine () is infinite, so that this fraction becomes zero and the efficiency becomes 1.

the answer is f1 and d2 because if you put equal force on those two points the beam would balance trust me on this