Question

a man of 60 kg climbs up a staircase carrying a load of 20 kg on his head. the staircase has 20 steps each of height 0.20m. if he takes 10 J TO CLIMB . FIND HIS POWER . TAKE g= 9.8 m/s

Answer 1

Force acting on the man (60+ 20 ) = 80 X 10 =800 N
where 20 kg is the mass of the load
Distance covered by the man in claiming 20 stairs
S= 20 X 0.20 =4 m
work done by the man against gravity
= 800 X 4 = 3200 J
As the man take (10 J ) $\mathbf{\to }$ it should be 10 min
t = 10 min = 10 X 60 = 600 sec
Power , $\mathit{P}\mathbf{}\mathbf{=}\frac{\mathbf{w}}{\mathbf{t}}\mathbf{}\mathbf{=}\frac{\mathbf{3200}}{\mathbf{600}}\mathbf{}\mathbf{=}\mathbf{5}\mathbf{.}\mathbf{3}\mathbf{}\mathbf{}\mathit{w}\mathit{a}\mathit{t}\mathit{t}$