Question

a man weighing 80 kg climbs a staircase carrying a 20kg load. the staircase has 40 steps each of 25 cm height . if he taked 20 sec to climb the work done is ans is 9800J please explanation​

Answer 1

Potential energy=mass×acceleration due to gravity x−heightPotential energy=mass×acceleration due to gravity x−height

P.E.=m×g×hP.E.=m×g×h

According to the given condition -  

m=80+20=100kgm=80+20=100kg

g=9.8m/s2g=9.8m/s2

h=25×40=1000cm=1mh=25×40=1000cm=1m

P.E=Work Done=100×9.8×1=980JP.E=Work Done=100×9.8×1=980J

Power is rate of work done =Work DoneTime Taken=98020=49J/s=49Work DoneTime Taken=98020=49J/s=49Watt

I'm extremely sorry if its too messy because i was in a hurry.my exams are going on.

anyways hope it helps