Question

it takes for 20 seconds for a person a of mass 50 kg to climb up the stairs while another person b of same mass does the the same in 15 seconds compare the work done and power developed by the person a and b


ANS WORK DONE=1:1 POWER DEVELOPED =3:4​

Answer 1

For case of A,

Mass = 50kg

time = 20s

Displacement = d

acceleration = g

{we are taking Acceleration die to gravity cause they are climbing stairs}

Work done = Force × displacement

=> mass × acceleration × displacement

=> 50gd

Power = Work/time

=> 50gd/20

For Case of B,

Mass = 50kg

time = 15 seconds

acceleration = g

displacement = d

{g and displacement will remain the same for B too}

Similarly,

Work done = 50ad

Power = 50gd/15

Ratio of work done by A and B = 50gd/50gd = 1:1

Therefore Work done = 1:1

Ratio of their powers =

$\frac{ \frac{50gd}{15} }{ \frac{50gd}{20} }$

20/15

4:3

Ratio of their powers = 4:3

Cheers!