A typical student listening attentively to a physics lecture has a heat output of 100 w. how much heat energy does a class of 170 physics students release into a lecture hall over the course of a 50 min lecture?

Since each student emits 100 W, so 170 students will emit:

total heat = 100 W * 170 = 17,000 W

Convert minutes to seconds:

time = 50 min * (60 s / min) = 3000 s

The energy is therefore:

E = 17,000 W * 3000 s

E = 51 x 10^6 J = 51 MJ