A 64.4-kg firefighter climbs a flight of stairs 21.3-m high. How much work (in J) does he do?

Work done by firefighter = 13456.57 J

Explanation:

Here work done is equal to potential energy gained by him.

Potential energy, PE = mgh, where m is the mass, g is acceleration due to gravity value and h is the height.

Mass, m = 64.4 kg

Acceleration due to gravity, g = 9.8 m/s²

Height, h = 21.3 m

Substituting

Potential energy, PE = mgh = 64.4 x 9.81 x 21.3 = 13456.57 J

Work done by firefighter = 13456.57 J