Question

Two girls, A and B each of weight 400 N climb up a rope through a height of 8 m. Girl A takes 20 s while Girl B takes 50 s to accomplish this task. What is the power expended by each girl​

Answer 1

Solution

Given,

• two girls A and B each of weight for hundred Newton climb up drove through a height of 8 m .
• girl A takes 20s .
• girl B takes 50s .

To find ,

• we have to find here the power expended by each girl .

i) power expended by girl A ;

• weight of the girl ,mg = 400N
• displacement (height) = 8m
• time taken , t = 20 s

So,

• we know that power = work done / time taken

=> mgh / t

=> 400n × 8m / 20s

=> 160 w .

ii) power expended by girl B ;

• weight of the girl , mg = 400n
• displacement ( height ) = 8m
• time taken , t = 50 s

now to find p [ p = mgh/t ]

=> 400n ×8m/50s

=> 64 w

The power expended by girl A is 160 w and power expended by girl B is 64w .