Question

it takes 20 s for a person A to climb up the
stairs, while another person B does the same
in 45 s and both having same mass. Find

(a) Ratio of works done by A and B.

(b) Ratio of powers expended by A and B.​

Answer 1

The work done by persons A and B is independent of time. Hence both A and B will do the same amount of work. Hence,

work done by A=1

work done by B=1

1:1

(ii)Power developed by the person A and B is calculated as follows: A takes 20 s to climb the stairs while B takes 15 s, to do the same. Hence B does work at a much faster rate than A; more power is spent by B. Power developed oc 1/time (and amount of work done is same)

power develop by A=15

power develop by B=20

3:4