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

Step-by-step 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)=-(1)/(2)mv_f^2+mgh_i`

`\Delta E_(th)=-193.2+3292.8`

`\Delta E_(th)=3099.2 J`