When he reaches the bottom, 4.2 m below his starting point, his speed is 2.2 m/s . By how much has thermal energy increased during his slide

Complete question:

A fireman of mass 80 kg slides down a pole. When he reaches the bottom, 4.2 m below his starting point, his speed is 2.2 m/s. By how much has thermal energy increased during his slide?

The thermal energy increased by 3,099.2 J

Explanation:

Given;

mass of the fireman, m = 80 kg

initial position of the fireman, hi = 4.2 m

final speed, v = 2.2 m/s

The change in the thermal energy is calculated as;

ΔE +  (K.Ef - K.Ei) + (Uf - Ui) = 0

where;

ΔE is the change in the thermal energy

K.Ef is the final kinetic energy

K.Ei is the initial kinetic energy

Uf is the final potential energy

Ui is the initial potential energy

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