Question

A fireman of mass 80 kg slides down a pole. For the steps and strategies involved in solving a similar problem, you may view a Video Tutor Solution. Part A 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?

Answer 1

Answer:

Explanation:

Given

mass of Fireman $m=80 kg$

length of Pole $L=4.2 m$

His speed $v_f=2.2 m/s$

Considering Pole,Fireman and Earth as system

since no Energy comes in and out therefore $\Delta E=0$

$\Delta E=E_f-E_i$

$K_f+U_f+(E_{th})_f-K_i+U_i+(E_{th})_i=0$

where K=kinetic Energy

U=Potential Energy

$E_{th}=Thermal\ Energy$

$(k_f-K_i)+(U_f-U_i)+\Delta E_{th}=0$

$\Delta E_{th}=(k_i-K_f)+U_i-U_f$

$\Delta E_{th}=-\frac{1}{2}mv_f^2+mgh_i$

$\Delta E_{th}=-193.2+3292.8$

$\Delta E_{th}=3099.2 J$