A man whose mass is 50 kg climbs up 20 steps of the stairs with mass of 20 kg on his head .If each step of stair is 0.25 m in height , then work done by a man will be ………

A man whose mass is 50 kg climbs up 20 steps of the stairs with mass o

1.	A man whose mass is 50 kg climbs up 20 steps of the stairs with mass of 20 kg on his head .If each step of stair is 0.25 m in height , then work done by a man will be ………
Answer» 475 J 3500 J 1715 J 3430 J Solution :TOTAL mass m = mass of man + mass on head ` = 50 +20` ` = 70 kg ` Height increases = height of one step `xx` total no of STEPS , ` = 0.25 xx20` ` = 5 m ` ` :.` Work W = change in potential energy = mgh ` = 70 xx 9.8 xx 5` = 3430 J